A Word about Air and an Air about Words

A Word about Air and an Air about Words • The fact that humans have actually walked on the airless Moon is amazing. In my fantasy, humans could survive on the moon without the assistance of space suits by sucking oxygen out of moon rocks. • Such people, however, would be totally dependent upon sign language. This is not only because their mouths would be full of rocks, but also because there is no atmosphere on the moon to carry a sound wave. • On Earth we have atmosphere and, hence, we have sound. We think, and communicate in words and sentences which are composed of units of sound. • It's the air, then, that makes oral language possible. Let's look at this phenomenon and see how it basically works and how it effects speech and language when it doesn't. • We will be looking at three aspects of sound in air: Frequency, Intensity and Phase. Frequency is the number of times per second (cycles per second) that a molecule of air bounces (oscillates) back and forth. • Frequency and Pitch: What happens when I speak? Does my vocal fold hit a molecule of air to send it rebounding off the back of my throat, ricocheting around my mouth a few times, and then hurdling out across the room until it strikes someone's ear? • Fortunately, for good hygiene, the answer is no. The action of the molecule is more like that of domino. You‰ve heard of the "domino effect." This is where they line up a row of many dominos. • When one is pushed over, it knocks the next one over in line, and so forth. You can watch the energy propagate itself along the line, although no domino moves farther then its length. • There is one big difference. The domino just lies there, whereas a molecule of air bounces back like a ping pong ball. If the vocal folds are still moving, the molecule gets whacked repeatedly and bounces back again, and again and again. • Count the number of times this happens each second and you have what is called, the frequency. We experience frequency as a range of Pitches from low (around 50 Hz) to high (around 20,000 Hz). • Of course, not one, but many molecules are involved, and as they hit the next molecule layer as a group, we have a band of compressed air, followed by a band of rarified air. • This band expands in all directions like a balloon. And since the process is repeated, it is really more like an expanding balloon within a balloon within a balloon etc. Each balloon represents one cycle per second (cps). • Not that anybody calls it cycles per second anymore. In this age of high technology, that was too simple, so they changed it to Hz, in honor of a German physicist (Von Hertz). • Oscillating is what the molecules of air are doing, and that is called Frequency. How we experience or perceive it is called Pitch. Our ears can detect a range of pitches from as low as 50 cps (excuse me, Hz) to around 20,000 Hz. Our most sensitive hearing is in the range of frequencies that speech sounds are produced. • Of course we don‰t hear each frequency equally well. The lower and higher frequencies require progressively louder sounds for us to hear. Our best hearing range for pitches is from around 400 Hz to about 5000 Hz. • Happily, this is the same range at which speech sounds are generated! Were this not so we might all have to talk much louder to be understood. • As we are all aware, speech sounds are divided into two groups--vowels, and consonants. But what we often don‰t think of is that as a group, vowels are low frequency sounds (extending a little above 1000 Hz); and consonants are high frequency sounds, (extending only a little below 1000 Hz). • What makes this significant, is that consonants, taken as a group, are more important than vowels for speech intelligibility. Consonants are high frequency sounds that are critical to understanding speech. • Think about it, would you prefer to spend the rest of your life speaking only consonants or vowels? Here is a sentence with vowels only... • "I oe ou a uera ay ai!" • Here is a similar sentence in consonants only... • "Wth cnsnts y cn lmst ndrstnd vr thng!" • You will see the impact of this later when we discuss hearing and types of hearing loss. We will discuss a sensory neural (nerve) loss that often effects more radically the higher frequencies. Hence, babies can be born with a high frequency loss that would preclude their hearing consonants but not speech. • • These children would appear anything but deaf since they would respond to sounds, even soft ones (because of their low frequency components); but would not develop language or speech because they couldn't hear the consonants. A Pure Tone occurs when a molecule oscillates regularly and smoothly back and forth. • A single molecule oscillating up and down as a result of a noise would leave a tracing of its movement as a straight line. • If a more steady sound lasted for a second while I pulled the monitor screen to the left, the tracing of the movement of the molecule might look like this: This is a description of how this molecule moves in time--smoothly and regularly (Periodic). This one would be called a Pure Tone. • Tones have Periodic (regular) oscillations, but Noise has Aperiodic (irregular) movements • A Pure Tone is also called a Sine Wave, because of the shape of the curve of the movement. It is also called sometimes a Simple Tone, because it represents a Single Frequency. • Hence, it is the smallest unit of sustained sound that one can have, as far as Tones are concerned. This, I suppose, means that there is another kind of sound other than a Tone. Yes, of course. • You remember how we described the movement of a molecule for a tone as being regular? Well you can have oscillations that are not regular. My wife says that this describes my dancing ability perfectly. Above it is a graphic representation of an Aperiodic sound It is called a Noise. • Vowels are tones and originate in the larynx, whereas consonants are noises and are generated in the vocal tract. • A point of interest is that Vowels, which are sounds generated by the larynx, are Tones (although by no means Simple or Pure Tones). • Consonants, on the other hand, which are sounds produced by constricting the air flow usually somewhere above the larynx (with the exception of /h/), are Noises. An increase in the range of molecular oscillations (Intensity) will be perceived as an increase in loudness. • Intensity and Loudness: If the energy producing a sound is increased, the frequency may stay the same, but the range of oscillations of the molecule will increase. • Hence, the molecules striking the ear drum will have more intensity and will be perceived as being a louder sound. • A curious feature of hearing is the range of degrees of loudness to which the ear can respond. The Threshold of hearing is the intensity level of a sound which is perceived by the listener fifty percent of the time. • At one end of the range is threshold, which may be defined as the intensity level of a sound which is perceived by the listener fifty percent of the time. • At the other end of the range is the intensity level where severe pain is experienced and damage to the ear is likely to occur. • If I arbitrarily set the threshold of hearing to a value of 1, the loudest sound the ear can handle without generating serious pain isá 10, 100, 1000, 10,000ámore ? • (Take a guess. The answer is on the next slide). • We are considerably interested in that range because it may differ between individuals, particularly in regards to the threshold value. • For some individuals, threshold may be raised considerably to the point where it is above the level of many environmental sounds. The range of hearing for loudness is so large that we must use a logarithmic scale to the base 10 to measure it. • If we start with 1, the loudest sound we can hear is: o 100,000,000,000,000,000 • Our problem now, if we want to test that range, is to develop an intensity dial that goes from 0 (no sound) to that number. Hall‰s attempt to make an Intensity Dial can be viewed in the Graphic Version. • • My intensity dial was a failure. I couldn‰t do it because it takes too many numbers to get to the top. That‰s. because I was using an Arithmetic scale. o 0, 1, 2, 3, 4, etc. • A Geometric scale would involve less numbers. For example: o 1, 10, 100, 1000, 10,000 etc. • But still the numbers are too large to fit on a dial. So we can use their log values. For example: o 100, 101, 102, 103, 104 etc. (That is supposed to read 10 to the zero, 10 to the first, 10 to the second, 10 to the third, etc.) • Since the above is all to the base 10, we can leave out 10 and just use the exponents like this: o 0, 1, 2, 3, 4, etc. Zero decibels (0dB) is the average threshold of hearing for the healthy adult ear. • The units of this logarithmic scale are called Bells (after Alexander Graham Bell. o 0Bells, 1Bells, 2Bells, 3Bells, 4 Bells, etc. • Of course, nobody uses this scale now because the units are too large, just like one dollar is too large for many things we want to purchase. Hence, just like one dollar is broken up into 10 dimes, one Bell is equal to 10 decibels (dB). This is the unit o 0dB, 10dB, 20dB, 30dB, 40dB, etc. • A person with a hearing level at 4 Bells (40dB), would require a tone 10,000 times more intense than a person with a normal threshold (0 dB). • At 3 Bells (30dB), the tone would have to be 1,000 times more intense. • At 2 Bells (20dB), the tone would have to be 100 times more intense. • At 10 Bells (10dB), the tone would have to be 10 times more intense. Although it changes a little for each frequency, the air pressure at 0dB is about .0002dynes/cm2 • At 0 Bells (dB), a tone would equal the intensity that is accepted to be the standard normal threshold for the healthy adult ear. • Zero, in an arithmetic scale, would mean a total absence of sound. • But 0dB is a logarithmic scale and hence does NOT mean a total absence of sound. It represents the pressure of the sound at threshold, which for most frequencies is close to .0002 dynes/cm2 . • The dynes/cm2 unit is a more appropriate measure here than pounds/in2, because of the delicate nature of the eardrum and its sensitivity to very minute pressures. • If 0dB is a positive intensity level, then there must be smaller (lesser) intensities. • Hence, a person with a threshold of -10dB can hear a tone at 1/10 of the intensity level of a person with 0 dB threshold. A hearing threshold of 30dB or more for most frequencies in both ears would cause a significant speech and language problem • I have known some young children to test as low as (minus) -30dB! • As a very gross rule of thumb (to serve our purposes here in describing speech and language development) I am going to say that any hearing threshold 20dB or below is within the normal range. • Also, (as a gross rule of thumb) any threshold 30dB or greater will pose a significant problem for language/speech development and use. • That is, providing the loss is for most frequencies in both ears. You can develop speech and language in a normal fashion with just one good ear. • So what are the chances that a person would have a 30db loss in most frequencies of both ears? Unfortunately very good! • The highest incidence of hearing loss in the United States is due to middle ear infections, which are very common in young children. Phase is the interaction of two tones generated simultaneously. • Phase and Familiarity: So far we've been talking about pure tones, which actually don't occur naturally in nature. So what do we hear in nature? • Complex tones occur in nature. They are combinations of pure tones, much like a brick wall is composed of bricks. • One difference is that the bricks in a wall are all the same size. The pure tones in a Complex tone are all different sizes, or more correctly, frequencies. • Not just any two pure tones will combine, moreover. They must be integral multiples of each other, like 125 Hz, 250 Hz, 500 Hz and 1000 Hz etc. • Actually if two pure tones of the same frequency and intensity are produced simultaneously, they will combine. If they are in phase (i.e.,the molecules move in the same direction at the same time) the result will be only one pure tone that is louder. If two pure tones of the same frequency and intensity occur simultaneously out of phase, they will cancel each other out. • If two pure tones are produced simultaneously, but are directly out of phase (i.e., the molecules of air are moving in exactly the opposite direction) the result will be no sound at all! That is because all the energy is cancelled out. • For example, if I am pulling on a table and you are pushing on it equally hard; and then I push on it and you pull on it equally hard, the end result will be no movement of the table. • In some auditoriums that have not been carefully acoustically designed, you can be sitting right in the front row and hear hardly anything because you are in a "dead spot" (I.e., a spot where the sound bouncing off the walls reflects back out of phase an • There are delay feedback mechanisms now on the market, which play back environmental noises out of phase creating almost a quiet world for an individual who wears the earphones. If two pure tones of different frequencies occur simultaneously they will cause fluctuations in the smooth curve to create a Complex tone. • These noise suppressors are reminiscent of Maxwell Smarts "Cone of Silence," (if you are old enough to remember the TV show "Get Smart.") • On the other hand, I have an unconfirmed report that there is a spot in the U.S. Senate Chambers where sounds are reflected back in phase and amplify confidential whispers made across the room. • What happens if the to two simultaneous pure tones are different frequencies and are integral multiples of each other? • Obviously, they can't cancel each other out. But they do combine in an alternating enhancing and inhibitory fashion. • The end result is that the smooth curve of the sine wave (pure tone) becomes bumpy. If more pure tones are added (being all integral multiples) the curve becomes even more bumpy. This now describes a Complex Tone. The Fundamental in a Complex tone determines the pitch, and the pattern of Overtones determines the quality. • If one starts with a Complex tone it is possible (if you are a math nerd) to tease out and identify the pure tones that originally combined to create the sound. That process is called Fourier Analysis. • Through this analysis we would discover that a complex tone has an array of pure tones, each having a different frequency. The lowest frequency is called the Fundamental. Whatever it is, determines the pitch of the sound we hear. • All of the other (higher) frequencies are called overtones. • They form a particular pattern, like 4 8 16 thousand cycles or, 4, 16, 32 etc. Whatever that pattern is determines the quality of the sound. It is the quality that makes a sound recognizable or familiar. • Even our voice has a particular pattern of overtones that makes us sound like us. They have been referred to as Voice Prints. • It is the pattern of overtones that are changed in a process called resonation (we will talk about that later) to produce the different vowel sounds of speech. As the mass of a vibrating body increases, its frequency decreases, but as the tension increases the frequency also increases. • Mass and Tension: Any object that can vibrate is capable of creating a tone. Two factors determine the frequency of the vibration: the Mass of the object and its Tension. • As the Mass is increased, the frequency and hence the pitch decrease. This is quite familiar to most of us. For example, the thick strings on a piano or a guitar produce the lower tones. • Men in general have more mass in their vocal folds than women and hence, have lower voices. • On the other hand as the Tension of a vibrating body is increased, the frequency increases. This also is quite familiar to most of us who have plucked a guitar string while turning the screw to increase the tension of the string. The pitch rises as we turn the screw. The pitch of one's voice is raised by increasing the muscle tension on the vocal folds in the larynx. • Those of us who couldn't afford a guitar have probably had an equivalent experience by progressively stretching and plucking a rubber band which we held at one end between our teeth. • We would hear a definite increase in the pitch of the resulting "twang" sound, usually for several strums before we felt the excruciating pain of the rubber band as it broke and snapped back. • Then, of course, you would hear the high pitch of someone yelling. • We achieve a high vocal pitch, incidentally, by tightening the muscles associated with the vocal folds to increase their tension, much in the same fashion that we pull back on the reins of a horse. • Some people who live in the "fast lane" find through life a constant need to be on the "red alert". These individuals are often described as "High Strung." A person who is tense may have a habitually higher pitched voice that would be predicted from the mass of his vocal folds. • A high strung individual may generally hold their body musculature at a higher level of tension than is necessary. This can include the muscles of the neck and larynx. • The result of the increased tension on the vocal folds is a habitually higher pitched voice than would be predicted from the size (mass) of their vocal folds. • This can actually cause undo wear and tear on the folds resulting in various types of voice disorders. • A pitch related voice problem confronts boys particularly at around the age of puberty. At this time, the influx of hormones causes, among other things, an inordinate rate of growth of the vocal folds. The increased mass causes the voice to drop in pitch. • Two other factors exacerbate the problem. The first is the role our voice plays in society, The other is the significance of our voice to ourselves. Our face and our voice are two important passports, that determine if and how we will be accepted into society. • The Role of our voice in Society: I always imaged myself to be a good candidate to become a self sufficient solitary mountain man type. I find however, that in reality, 30 minutes into Griffith Park begins to bring on withdrawal symptoms for my health food store, my exercise gym, and my room where my internet connections await. • I am compelled, now, to admit that I am very dependent upon society! • What's more I believe most of use are. But ironically, we need passports to be accepted by others in Society. • One important passport is our face. If I had no nose and no upper lip, but just a gaping hole, the students in my class on campus would cluster in the back of the room rather than choose seats up front. • Come to think of it, they are clustered in the back of the room. What can I say--some people have better passports than others. Our Voice is a major component of our Self Concept • You can imagine where the students (who are predominantly women) would be sitting if Tom Cruise were teaching the course. My wife would even come to class! • Another major passport is our voice. If I had a very high pitched squeaky voice, it would be hard to win acceptance as a leader of men. I doubt if I could ever be elected president. • We are subconsciously aware of these passports, and as a result show major concern for things that diminish them. • How we hate to have warts and wrinkles on our face; or an aberration to our voice quality and/or articulation. • The significance of our voice to ourselves: One of our most singularly important possessions is our self concept. As part of this, we are obviously very fond of our body parts and feel great loss, over and above the inconvenience, when one of them is amputated. • One of the most important body parts, ironically, is not strictly a body part at all--the voice. When the teenager's voice begins to change, a major part of his self concept is threatened. • Whereas we see little of our body parts unless you carry a full length mirror around, as I do. But we do constantly hear our voice. It is almost symbolic of our daily existence and who we are. If we lose our voice, we have almost lost ourselves! • Now we can begin to see the potentially massive psychological problem that is confronting the young teenage boy as his vocal folds begin to rapidly increase in mass. • His voice begins to drop in pitch. His "Comparitor" sends error messages to the Mixer that the pitch is not right. The Mixer sends messages to the larynx to raise the pitch. • But this is becoming more difficult as the mass of the folds continually increases. • There will be frequent sudden pitch breaks. The resulting deep voice is an aberration -- not part of the teenagers concept of himself. What's more people may laugh. In a desperate attempt to maintain the status quo for vocal pitch, some teenagers may adopt a falsetto register. • All this, of course, is occurring at a time of life when the teenager‰s concept of himself is most liable anyway. Teenagers are struggling for self identity as their bodies and social roles change, and then their voices begin to go haywire. • Still most teenagers cope with it and eventually accept the change. A few, however, find it overwhelming. • In a desparate attempt to keep their pitch close to what it was, at least in their minds, and to preserve their self concept, they throw their voices into a falsetto register which is now more easily sustainable. • Although people may be startled to see a six foot, 200 pound volatile teenager with a voice like Shirley Temple, they may elect to say nothing about it in his presence so as not to aggravate him. If mass and tension of a vibrating object are held constant, there will be one frequency at which it vibrates best. • But in time the problem becomes increasingly compelling. An inability to get preferred jobs or dates drives the now young man to seek professional help. • A speech pathologist may be able to correct the voice in 30 minutes, but it may take a year of counseling for the young man to accept and use the "new" voice in public. But back to mass and tension. • What happens if the mass of a vibrating object is held constant and the tension is not changed? • Under these conditions there will be one frequency at which that object vibrates best. That frequency is called the Natural Frequency. • The farther away in frequencies an object vibrates from its natural frequency, the more intensity it requires to produce a desired loudness. • Take, for example, the person who speaks habitually at a higher pitch than their natural frequency. A body will resonate if the original vibration matches the Natural frequency of the resonator. • The vocal folds of a person who speaks too high (or too low) have to work much harder to maintain a desired loudness. • This abuse to the folds leaves the door open in time for a myriad of voice disorders. • Resonance: Some vibrating objects are not the original source of the vibration. They are set in motion by some other vibrating object. Probably most people have witnessed a window that vibrates when a vehicle, maybe a truck, passes by. • What is important is that not every vehicle that passes causes the window to vibrate. Only those engines which generate sound waves that match the natural frequency of the window will start it to vibrate. • Another example is that when soldiers march across a bridge, they are told to break cadence. Otherwise, if they all happen to be stepping in time to the natural frequency of the bridge, they can cause it to resonate so violently that it will actually collapse. A resonator is a screen that lets some frequencies of a complex tone through while inhibiting others. • There was a case of a large suspension bridge in Washington State (the Tacoma Narrows Bridge) which in 1940 was whipped so vehemently by wind gusts which matched the natural frequency of the bridge that it collapsed. You can see this in the notes below. • The point is that frequencies that match the natural frequency of a resonator are facilitated whereas those that do not match are inhibited. • Hence, the resonator acts as a screen which can eliminate some frequencies in a complex tone while facilitating others. • This is the function of the modulators, which we will discuss soon as part of the Expressive Transducer for the Aural Modality (e.g., the mechanism of speech). We will discuss how they change the pattern of overtones produced by the larynx to create the vowel sounds of speech. The Expressive Transducer, and What Babies Hear • In Mysak's model, we described the Expressive Transducer in three parts: the Motor, the Generator and the Modulators. • Motor: This refers to the source of energy for speech, and if anything is going to happen muscles must be involved. Nowhere is this more true than for the speech act. • The first muscle we may all think of is the diaphragm. Actually, this is a domed shaped muscle when relaxed. • It separates the chest cavity from the abdominal cavity. When it is tensed, it flattens out, creating a partial vacuum in the chest cavity. Air will rush in through the nose, trachea ("wind pipe") and lungs to fill the space. • This is inhalation and as you can see it is an active process. There are many more muscles involved, however, in inhalation than just the diaphragm. When breathing for life, inhalation is active involving many muscles and exhalation is passive. • There are muscles between the ribs, and over the shoulders, some extending from the back of the head. • When the diaphragm flattens, these muscles combine to expand the ribcage. Even muscles low down in the back may be called upon to stabilize the spinal column. • Think of the massive timing process that the brain must habitually orchestrate to repeatedly coordinate all these muscles. • In contrast to inhalation which is so active and complicated, exhalation is the easiest thing we ever do (unless we have emphysema). • To breath out we simply relax and the elastic nature of the diaphragm returns it to its normal dome shape (helped by the push of the viscera which were compressed during inhalation). The chest cavity collapses helped by gravity. All this forces the air out. It is a totally passive process. When breathing for speech, exhalation is highly controlled, requiring special neurological circuitry which humans posses. • But when breathing for the purpose of speech, the exhalation process also becomes active and even more complicated. Now the breath is forced out through the vocal folds in a carefully controlled flow. • We do this effortlessly, partly because we have a large cadre of nerves devoted to the process. This is a genetic inheritance. "Ed" the "talking horse" and even "Koko" the signing gorilla could not really control the breath stream well enough to produce speech as humans do. • If you are not familiar with "Ed" check the notes. • Sometimes the process is pathologically disturbed. Cerebral Palsy children may have problems in coordinating the flow of speech and may find it difficult to get more than one word or sentence to a breath if at all. • Even some stutterers find the processes disrupted and the lack of coordination in breathing process is quite visible if not uncomfortable to watch. The Generator is a mechanism to produce sound , which is required for speech. • The purpose of respiration for speech, is to move air. Of course there are other muscles not involved with moving air which must nevertheless be coordinated with the breath stream. • These are the muscles of the soft palate (velum), the tongue, lips jaw, and the larynx. The function of the larynx, of course, is to generate the sounds for the vowels and many consonants. • Generator: The whole purpose of moving air is to create sound which can transmit a symbolic signal. There are a number of locations around the body, and particularly in the oral track were sounds can be made. Tapping with the feet is one example. "Donald Duck" talk using the back of the oral cavity is another. Using the feet takes considerable energy, and it's hard to find a time when the feet are not precoccupied with walking or standing. There are two passages leading from the oral cavity--one for food (Esophagus) and one for air (Trachea). • "Donald Duck" talk is very limited in its range of pitch and loudness, and constricts the tongue in its production. • Ironically, our generator, which is very effective and efficient comes to us perhaps through serendipity as a side effect of nature's attempt to solve a serious structural problem. • Visualize this. Here we have the oral cavity which is used for two purposes: Food intake and Air Intake. • The structural problem is this."They" placed our air intake tube (the trachea) in front of the foot intake tube (the esophagus). That means that every time you take a bite to eat, you must pass the food over the trachea. • Should a tiny morsel (like a sliced carrot or even a vitamin pill) fall into the trachea, we may have just five more minutes to live--and not a particularly fun five minutes either! If liquid or food gets down the wrong tube (the Trachea) we may get pneumonia or worse yet, quick asphyxiation. • And even if it's liquid, you might not choke but you then become a good candidate for pneumonia. And we swallow liquid (saliva) almost constantly. • I once challenged the class not to swallow for the entire period; and after 15 minutes we all looked like a pack of rabid writhing wretches. Because the class was mostly girls you could say that we were a "room of rabid writhing retching wenches." • Sorry about that, I just like tongue twisters. • Obviously most of us have not choked on our food nor gotten pneumonia. That is because nature has built in some safeguards. • At the top of the trachea, which is a cartilaginous ringed tube, is a valve "box" which can close the entrance to the tube. This is made up of two cartilaginous sections: the cricoid and the thyroid cartilage. The Larynx (not to be pronounced "Larnyx") is a valve system at the top of the Trachea to keep food out. • The cricoid cartilage is like the final ring of the Trachea, only somewhat more complex. The Thyroid cartilage is shaped like a shield attached to but placed in front of the cricoid cartilage. This is what people are seeing when they observe the "Adam's Apple." • This structure is commonly called the voice box, but more correctly it should be labeled the "Larynx." Caution, do not call it the "larnyx!" This can cause a major stroke in some speech professors. In the Larynx, the vocal folds open and close to let air pass and to keep food from falling down the Trachea. • Stretched across the opening of the cricoid cartilage are the two vocal folds made mostly of connective tissue. They are always closed in front at the point where they meet, but swing open and shut from the other rear. • The rapidity with which these folds can open and close (an alternating movement called diodochokenesis) is unparalleled in the body. When we swallow, the vocal folds close snuggly. There is actually another point of closure just above the folds called the False Vocal Folds. When the vocal folds are shut and air if forced through, they will vibrate and produce a sound. • The false vocal folds are not as well controlled as the real ones. But I have had at least one student who used them to vocalize. It was a real harsh sound and a problem for him because he couldn‰t use his regular folds. • Other mechanisms to keep food from being swallowed include the raising of the larynx during swallowing. You can actually see this on someone else as the "Adams Apple" goes up an down. • There is a cartilaginous slide over the entrance called the epiglottis, and folds along the side of the entrance to the larynx to catch particles of food. There is also a liberal system of cough reflexes to expel particles of food. Together, these safeguards work pretty well most of the time. • The serendipitous part for speech is that when the folds are shut and air is forced through, sound vibrations are produced. The only changes in sound we can make at the level of the larynx is to raise and lower the pitch and loudness. • The action of the vocal folds is much like that of the lips when we make the "Bronks Cheer." We hold our lips together firmly and force the air though to make them vibrate, albeit with a sputtering sound. • The vocal folds are much smaller, of course, and capable of faster and finer vibrations. The result is the beginnings of voice. Not that it sounds all that great, at that point. Originally, it is really a rather pitiful squeak. It is left to the resonators to shape the vocalization into something we would recognize as a human voice. • • The only changes we can impose upon sound at the level of the larynx are to raise and lower the volume (which is really a matter of breath control) and to raise or lower the the pitch. The latter we do by changing the tension of the vocal folds. • Typically, the mass of the vocal folds remain constant. However, there is a rapid increase in mass for boys particularly, during puberty. When the vocal folds are abused they may swell, which causes a drop in the pitch of the voice. • Also, when we get a cold, the irritating secretions generated by the sickness, or the wear and tear on the vocal folds created by the frequent coughing spasms may cause them to become swollen. • The increased mass gives rise to a deeper fundamental tone and hence, a deeper voice. We then say that we sound like we have a "frog in our throat." • Yelling a lot can cause the same problem. • If yelling persists it can cause calluses to grow on the folds. These are called vocal nodules. Vocal Nodules diminish the naturally smooth seal between the folds. This requires more energy to produce a tone and causes even more damage to the folds. • Eventually the calluses become as hard as fingernails and are difficult to get rid of. The voice quality is typically unpleasant--low, harsh and breathy. The greatest threat to the health of the vocal folds is smoking. • Vocal abuse and its consequence of vocal nodules can be a major problem for young singers. If they have not learned proper techniques, they will often require more intensity to sing than is typically necessary and healthy for the folds. Tragically the drive to keep performing eventually ends in the inability to keep singing at all. • The greatest single threat to the vocal folds, however, is smoking! The caustic nature of cigarette smoke with it cyanide, and many other poisonous gases acts to suppress the immune system. • This in general creates more frequent sicknesses and slower healing processes, and eventually a very high risk for cancer of the larynx. What may be worse to some people, of course, is that smoking causes deep creases in our favorite passport--the face. • The good news about laryngeal cancer is that it is easily detected. The pitch of the voice typically drops noticeably which eventually catches the patient‰s and the doctor‰s attention. A person who has his/her larynx removed is called a laryngectomee. • The bad news is the threat to life that laryngeal cancer poses because of its proximity to many lymph nodes in the neck. Should the cancer break through to these nodes it could be spread throughout the body. • The good news is that this can be totally prevented in many cases by totally removing the larynx (laryngectome). • The bad news is that once this is done, there is no valve at the top of the trachea to prevent food and liquid from spilling into the Trachea. • The good news is that this can be remedied by attaching the upper end of the trachea to a hole (stoma) in the neck. The patient then breathes though this hole in his/her neck. Now, there is no connection from the lungs to the mouth. • The bad news, of course, is that there is now no vocal folds nor air flow to produce sound for speech. Its hard for any one to imagine the isolation that people experience when they can't speak. A laryngectomee has no voice, and must use an artificial larynx or esophageal speech to communicate. • Writing is not a good substitute for conversational speech. Sign Language is, but more often than not, the community of the patient does not know Sign Language and is reluctant to learn. • The good news is that there are alternatives. Since it is the generator that has been lost, if we can find another, we are back in business. • We have already mentioned "Donald Duck" talk with the back of the oral cavity. • A more viable source of vibration is the esophagus. Everyone has "burped" sometime in their life. If they "mouthed" a word as they did so, they could produce an audible word or two. • Esophageal speech is based on the same principle. Only small amounts of air are injected by the tongue into the top entrance of the esophagus where it is forced out again with a vibration. Esophageal speech takes time and effort to learn, and the artificial larynx sounds mechanical. • The bad news is that, as a passport to society, there is much to be desired. In the notes below I give an example of esophageal speech. When I do this in class, many students report they feel ill. • The good news is that with practice you can improve. In the Movie QB VII, the actor who played the Judge was a laryngectomee and was using esophageal speech. I highly recommend renting the video to observe this actor. Its an excellent movie, too. • The alternative to esophageal speech is to obtain an artificial source of vibration. Battery operated oscillators can be placed on the throat or cheek to cause the oral cavity to resonate. • If the words are then "mouthed," audible speech is produced. An advantage of this over esophageal speech is that longer sentences can be produced, and little practice is needed. The disadvantage is that it sounds very mechanical. Juvenile Pappiloma is an aggressive growth on the larynx of some young children that requires medical attention. • Actually, the best advise is to not smoke. The human voice without question the best of all passports. Not that people don't get laryngeal cancer form other causes. Sometimes it is unavoidable. • But every time I see a teenager "light up," I feel sad because somehow I feel that that should have been avoidable. The message should, but is not getting through. • Juvenile Pappiloma is another type of growth on the vocal folds that afflicts some young children. Its like having warts that grow very fast. Although it effects the voice, the major concern is breathing. • The growths must be surgically removed many times. Fortunately, they frequently cease to be a problem after puberty. A series of resonating air chambers above the larynx alter the overtones to create the human voice. • There are three major resonating cavities above the larynx: The Pharynx, the Nasal Cavity and the Oral Cavity. • The pharynx (not the be pronounced ‹pharnyxŠ) is the area directly above the the larynx, in the back of the throat up to the oral cavity. • It is not typically changed during speech, although under conditions of overall body tension, it can be constricted. • Modulator: The complex tone produced by the larynx alone does not particularly sound human. It is the action of the resonating air chambers above the larynx that shape the sound into its human form by screening, and hence modifying, the pattern of overtones. • Air in an open area does not typically resonate, but in an enclosed areas, such as a bottle it will. Hence, the cavities in the air channels leading to the larynx can serve as resonators. The Pharynx and the Nasal Cavity are two resonating cavities that shape the sound produced by the Larynx. • Constricting the pharynx typically degrades the quality of the resonation. However, voice impersonators, like Rich Little, do amazing things by bring this resonator under voluntary control. • Others of us find an improved quality of voice when we learn to relax the muscles around the pharynx. Bing Crosby was probably the most relaxed man on earth when he sang. • The Nasal cavity is well known to anybody (everybody) who has had a head cold and has experienced the discomfort of having a stuffy nose. Try to say under those conditions the phrase ("Eminent Women.") It comes out ("Ebidedt Wobed"). • Ironically, in English, there are only three sounds that use nasal resonance (i.e., are produced with the soft palate {velum} open.) Only three sounds in English use Nasal Resonance.: "m," "n," and "ng." • The only three nasal phonemes in English are: "m" as in "mam," "n" as in "non," and "ng" as in "‹bong." • If you prolong those three sounds while placing your fingers on the side of your nose, you can feel the resonance. Try it and then alternate making a non nasal sounds (i.e., any vowel or other consonant). • Although there are only three nasal phonemes, they occur in speech with an especially high frequency. • Sometimes if a child‰s movement of the velum is sluggish, the sounds on either side of a nasal phoneme may also acquire a nasal resonance. This is called assimilation, and would occur in a word like, "man;" but not in "pat." • When vowels are nasalized, they are still recognizable, although the resonance may sound a little whiney. The Oral Cavity is the major Modulator of the three resonating cavities. • When consonants other than Ñm, n and ngÉ are nasalized, they become unintelligible. This is because the air pressure needed to make a consonant escapes through the nose. • The Oral Cavity is the most amazing of all resonators. It is a modulator in that it can easily change in many ways the nature of the overtones generated by the larynx. • Using the articulators (particularly the jaw and the tongue) the size of the air masses in the oral cavity can be easily and quickly modified. • This is one major advantage of oral speech over Sign Language. The latter requires considerable effort (relatively speaking). My class on campus, which is three hours long, requires at least two Sign Language Interpreters. One only for the whole three hours would be a good candidate for Carpal Tunnel Syndrome. The Oral Cavity can produce phonemes with a minimal expenditure of movement and energy. • So relatively minimal is the movements for speech, that I have never heard of a single professor coming down with Carpal Tunnel Syndrome of the Tongue. • To the contrary, the tongue is the strongest muscle in the body (inch for inch), and has a large quantity of neural tissue in the brain devoted to it's control. • It can assume a number of different shapes in the oral cavity with a minimum expenditure of energy. • For example it can arch in the front, middle or back; and can at the same time be raised or lowered. • As the air masses around the tongue in the oral cavity are changed (thus changing the natural frequencies) their screening potential for overtones changes. Each change in the pattern of overtones creates a new vowel sound. • Actually, that is only partly true, because we do not really produce discrete phonemes. What do we do? Actually, speech is not a series of discrete phonemes, but a continuous modulated flow of vocalized sound. • What we produce in speech is a continuous flow of modulated frequencies. You get a notion of how this sounds when you play speech backwards. • It is in truth, the listener, who superimposes his/her own template (expectancies) of phonemes on perceived running speech, that turns the continuous flow into apparent sequences of discrete phonemes. • That's one of the factors that makes foreign languages so difficult to learn for adults. • As an English speaker, when I hear Japanese, I automatically try to fit the stream of sounds into English phonemes. As a result I will fail to hear many important phonemes that are not in the English Language. • But what do babies, who have not had time to develop a template of phonemes, hear? They simply hear the continuous modulated flow of speech. How, then, do they develop the template? Babies do not perceive phonemes, but instead can hear all of the distinctive features that build the phonemes of every language. • Babies hear no phonemes in those first few months of life. • Ironically, however, their hearing is fully functioning by the time of birth. In addition, they possess some rather amazing auditory perceptual skills, apparently wired in before birth, which make them in some ways superior listeners to adults. • Whereas they don't hear the phonemes of a language, they can perceive the building blocks (the distinctive features) of all languages! • It is believed that the neural connections for distinctive features that are reinforced by the environment are strengthened, while those that are not stimulated are lost. • Hence in adulthood, my ability to hear the distinctive features that contribute to phonemes of languages not spoken in the home when I was a child, is lost. • A good example is Voice Onset Time. Voice Onset Time is a good example of a distinctive feature that babies perceive, but we as adults may not. • In English, if we start the laryngeal tone exactly at the beginning of the "P" sound, it becomes (is perceived as) the "B" sound. If we delay progressively longer in small increments the beginning of the voice (voice onset time), there is a point in time that it would become the "P" sound. If a line under the wordd represents the beginning of the voice, it would look like this: • BIT • PIT • Because as babies, we were exposed to verbal experiences in which those phonemic boundaries were used, we can discriminate these sound differences today. • But there are some languages that include a Voice Onset time before the beginning of the consonant: • BIT • _BIT • If the two words above were spoken and heard by a speaker of such a language, the two would be heard as different words--although to us they would sound and be the same. It is advantageous to have speakers of other languages talk to babies who are not high risks for language delay. • This is certainly one good argument for having family members who speak other languages talk to babies while they are young, to reinforce those neural tracks. This of course applies to babies who are not high risk for language delay. • I was asked in class if it would be beneficial to play language records in the presence of the child when they are babies. This would be an interesting topic for a doctoral dissertation for someone who has a baby and doesn‰t mind the background clamor. • Please let me know the results of your findings! • So what are those distinctive features that babies hear. There are books written on them. If you want to punish yourself severely for some indulgence, check one out on a Saturday evening and try to read it. In comparison, it makes a plumbing catalog seem like a romantic novel. • To give you a small flavor of what it is all about, we will limit ourselves to a discussion of just four each for vowels and consonants. The Place of Constriction of the air flow through the vocal tract is one distinctive feature for consonants. • The four Distinctive Features for Consonants, that I have selected to discuss, include the Place of Articulation, the Manner, the inclusion of • larynx (plus or minus voicing) and the inclusion of nasal resonance (plus or minus nasality resonance). Place of Articulation. The hallmark of a consonant is the constriction of the airflow somewhere on the vocal tract. This constriction creates a noise, as we discussed earlier. o There are certain locations along the oral tract (phonemic boundaries) where constriction has the potential to create a different phoneme. These locations can be described from front to back. Different languages select some boundaries that are the same and others that are different. o In English the most forward constriction boundary is the two lips (e.g., the bilabial "B"). The place of constriction can be described in terms of locations proceeding from front to back in the vocal tract. o There is, of course, the potential for a labio-nasal sound which no one has mastered yet. If you can master it you are eligible to receive the Grand Prize offered as an incentive in this course.* The sound is made by flinging the lower lip over the tip of the nose while expelling air through the mouth. Do not try this at home, however, but only near a medical setting. o *(The Grand Prize is: A full body size autographed photo of your instructor which can be placed in the living room.) o Getting back to English, and reality, the next place of constriction would be the lower lip on the upper teeth (e.g., the labio-dental "F"). This would be followed by the tongue between the teeth (e.g., the inter-dental "TH"); the tongue on the gum ridge (alveolar ridge for "T" and "S"); the tongue a little farther back on the palate (for "SH"); and the back of the tongue on the soft palate (velum for "K"). The baby is capable of perceiving the constriction boundaries of English and all other languages. o The farthest back you can go in English (and in any language as far as I know) is the glottis (the space between the vocal folds) to produce the "H" sound. Here we create air friction through the partially open folds, much as we do when we whisper. o o o In other languages, there are many intermediate locations for constriction that we don‰t have in English. An interesting one to me is the "X" sound in Russian, which to me sounds like "H" but is made farther forward. There is another one in Hebrew, which I wont even attempt to explain but it sounds to me like "Hkghshghghksh." I believe I did make that sound correctly by serendipity once during a heated discussion with my wife who was choking me at the time. The baby, of course, is capable of hearing all these boundaries, but in time will retain only those that are used in his/her presence. In vocalizations, back consonants appear first during the reflexive stages, but front consonants appear first in the voluntary stages. o In terms of sound production, the baby during the initial reflexive stages, of cooing and babbling, when there is little control of the articulators, will produce mainly the back consonants like "K," and "G." o This is not surprising since tongue tip control is not gained until later. Plus, the tongue is relatively large for the size of the oral cavity. At about six months of age, however, considerable voluntary control of the articulators is achieved. The child enters a new stage of vocalization called Lalling, which we will discuss later in another section. Under these circumstances the sounds we hear at first almost exclusively are the front consonants like "M," "B," and "D." o o o It is not surprising that the names of significant others to the baby in many languages are words that begin with front consonants, like "Mama," Dada," and "Baba." The Manner of Articulation is a second Distinctive Feature for Consonants. • The Manner of Articulation: Sometimes the point of constriction for two or more phonemes is the same. What differs is the manner in which they are made. Let me give three examples: Plosives, Fricatives and Affricates. o o o For Plosives, the air flow is completely blocked, thus creating a build-up of pressure. When the constriction is abruptly removed, the air escapes in with mini explosion (e.g., "P," "T" and "K"). For Fricatives, the constriction is only partial, thus creating some pressure build-up while at the same time letting air escape with a turbulence that creates a noise (e.g., "F," "TH," "S," and "Sh.") An Affricate is a phonemic "sandwich," that it is produced by both of the distinctive features, one top of the other. There are only two in English so we will use them as examples. The first is the first (or last) sound in the word "church." The addition of a tone from the Larynx (+Voicing) to the noise of a consonant provides a third distinctive feature. o The "CH" sound starts out as the plosive "T" and ends up as the fricative "SH." o Sometimes when a child has a lateral lisp for the "SH" sound (i.e., it sounds more like "SHL"), he/she will nevertheless make the "CH" sound correctly. When this happens, the "SH" part of this affricate can be use to teach the child to make the "SH" sound correctly. o The other example of an affricate is the first (and last) sound in the word "judge." This starts out as the plosive "D" and ends up as the fricative "Zsh" as in the word "vision." o • Voicing: Sometimes both the point of constriction for two or more phonemes and the manner are the same! What differs is whether or not a larngeal tone accompanies the air turbulence. The only difference between "P" and "B," for example, is that the latter includes a tone from the larynx. These pairs of sounds are called cognates. Nasality, a fourth distinctive feature of consonants, is used in only 3 phonemes in English: "M," "N," and "Ng." o Put your hand on your larynx and say "P" and "B" several times in succession. You can feel the vibration of the larynx on the "B" sound. Which one of the pairs of following cognates are voiced (have +Voicing): o PB DT FV SZ GK o Which of the two affricates that we discussed has +voicing? o o o o o The answers are "B," "D," "V," "Z," and "G." The affricate in "judge" is also voiced. • Nasality: Unlike French which includes nasal resonance in some vowels, no vowels in English include it. No consonants can be made either nasality with the excep�on these three: "M," "N," and "Ng." • There are many more dis�nc�ve features for consonants, but we'll leave these for all those linguis�cally brilliant babies to discover, and for those few lifeless speech pathologists or linguists to describe in a book The place of articulation for vowels refers to the arching action of the tongue to produce front, mid or back vowels. • • We will switch now to some (four) of the more interesting distinctive features of vowels. The four I have chosen to discuss are: The place of articulation; the height of articulation; tense versus lax vowels; and lip rounding. The Place of Articulation: This sounds suspiciously like a feature that we discussed earlier for consonants. But vowels don‰t involve the constriction of vocal air flow. In this case, place of articulation is referring to the contour of the tongue. o The tongue is capable of arching in different ways to partition the air masses in the oral cavity. o The vowels that are produced when the tongue arches toward the front are called front vowels. An example would be the vowel in the word:  "beat." o When the tongue arches toward the center, we have mid vowels produced, such as in the word:  "up." In vocalizations, front vowels appear first during the reflexive stages, but back vowels appear first in the voluntary stages. o When the tongue arches in the back we have back vowels. An example would be the vowel in the word:  "soon" o During the period of reflexive vocalizations for the baby, the vowels that will be heard most frequently are the front vowels. This makes some logical sense since the back of the tongue would occupied in the act of constricting the air flow for the consonants. o o Later as the child gains control over the articulators and voluntarily produces sounds, the back vowels will be heard initially more frequently. This is quite prevalent in early words like "Mama," and "Papa." The tongue raises and lowers to produce an array of front and back vowels. • The height of articulation: Not only does the tongue partition the air masses to produce front and back vowels, but it can be raised or lowered in the oral cavity to further modify them. o Thus a full array of front vowels can be produced from high to low as follows: "beat"  "bit"  "bait"  "bet"  "bat" For the back vowels, the array would be from high to low as follows:  o      "soon" "stood" "sow' "saw" "sod" o Although it is not absolutely necessary, most people drop their jaw when producing low vowels to provide more room for the tongue. This has considerable value in the process of speech (lip) reading. The position of the jaw will drop for low vowels to facilitate the movement of the tongue. o In lip reading the viewer has no way of knowing what the tongue is doing (because it is not visible). Hence, the only way that he/she can discriminate between words like "beat" and "bat" is to deduce the sound by observing the movement of the jaw. o I might add that Speech reading is not just for the deaf or hard of hearing. o We all use it when we are listening in a noisy environment and canÅt clearly hear the speech sounds. Then our gaze will subtly shift (often, without our even realizing it) from focusing on the speaker's eyes to observing his/her mouth. o o • Ironically, in these situations, our "hearing" seems to gets worse if the lights are dimmed. Tense versus Lax: A very subtle distinctive feature is the degree of tenseness exhibited by the tongue when producing certain vowels. For some vowels, the tongue is more relaxed than for others. o Both the highest front and back vowels, for example, are Tense. Some real examples are:  "Lean" (front) & "Luke" (back). o The next lower vowels are less tense or Lax. Examples are:  "Lynn" (front) and "Look" (back). o The mid vowel also, as in "up" is also Lax. o This is nothing as adults that we can readily feel or see. The muscle tension is orchestrated at a subliminal level during production. • Lip Rounding: Take a class in speech improvement and you will spend a lot of time practicing to round the lips when producing certain vowels. o Paradoxically, if you take a class in Ventriloquism, you will spend a lot of time practicing NOT to round the lips for the same sounds! How come? o Lip rounding is not essential for the production of any of the vowels. But it does have a place in vowel production. Lip rounding is more essential for lip reading than for sound production. o In English, there is a general tendency to round the lips for the back vowels. Try it and see...      "soon" "stood" "sow" "saw" "sod" o Alternately, we relatively draw the lips back for the front vowels. Try that too:  "beat"  "bit"  "bait"  "bet"  "bat" o Now for a fun experience say the back vowels (starting with "soon,") but make your lips draw back, as in a broad smile. It feels funny but with a little practice, you can do it. Try the front vowels above (starting with "beat") but purse your lips forward (i.e.,round your lips). Lip rounding is an important visual component in the perception of speech. o Where lip movements become really important is in the process of lip reading, which as I said, we all do. In a noisy environment we can tell from the lips whether the person said "beat" or "boot." If he rounded the lips, we know he said "boot." o And if he rounded the lips and dropped the jaw simultaneously, he probably said something like "bought." o Now, what happens if he says the word "bought" but doesn‰t purse the lips or drop the jaw? The word comes out fine but it is definitely difficult to lip read. o o If he says the word with no lip or jaw movement and at the same time vividly manipulates the mouth of a puppet, the movement will draw our attention visually. o We will perceive the puppet to be doing the talking. We have just experienced ventriloquists. Notice, that he did not "throw" his voice as many people believe. The key to good phonemic development is for the parents to spend much time talking to and around their baby. • Ventriloquism is not "throwing" the voice. It is, not moving the lips or the jaw. Even the consonants that require the front-most constriction can be accomplished by the tongue with some practice and will sound just fine. • These are just a few of the distinctive features (building blocks of phonemes) that the baby is equipped to hear at birth. • It remains for the parents to provide the materials (speech sounds) for the child to maintain and strengthen these listening skills. The child who sits alone for long hours in a crib will be at a disadvantage relative to the child who has doting parents hovering about and talking to and chatting about their child. • And if one of the parents is speaking another language, better yet for the baby's developing phonemic structure.