Table of contents
- What is child-directed speech
- What is adult-directed speech
- Introduction
- Conclusion
What is child-directed speech
“In comparison to adult-directed speech, CDS or motherese talk is characterized by a drastically altered vocal pitch, amplitude and speech rate. The vocabulary is simplified, and melodic patterns are noticeable (Broesch and Bryant 2015: 1). The main features that makes child different from adult-directed speeches are its short utterances and its omission of past tenses as well as the fewer disfluencies in sentences. It is known that infants prefer child-directed speech more as it includes shorter sentences, more repetition and a basic grammatical structure which makes learning more memorable.
What is adult-directed speech
Adult-directed speech is our everyday use of language; the language that we use to converse to our colleagues and family. “The main difference between children and adult speech is the fundamental frequency response. For children, they have shorter vocal track and smaller vocal fold. That is why children utterance have higher fundamental frequency than adults.” (Research gate)
Introduction
In this assignment, three different studies are discussed and critically analysed which helps emphasises that child-directed language is simpler than adult-directed language. These three studies are: Content words in Hebrew Child-directed speech (Tubul-Lavy, G.T. (2015)), Mothers’ “Baby Talk” Is Less Clear Than Their Adult Speech (APS) and An Acoustic comparison of vowel systems in adult-directed speech and child-directed speech: Evidence from French, English and Japanese (Dodane, C.D., 2007). The first study examines whether the “noun-bias” phenomenon exists in both the child and adult-direct speeches; the second study discovered that caregivers spoke less clearly in child-directed speeches whilst the third study conducted an acoustic comparison of the vowel sounds in child and adult-directed speeches.
The first study was by Tubul-Lavy, G.T. (2015) and his goal was to examine if the “noun-bias” phenomenon exists in both the child and adult-direct speeches and compared the different uses of content words when speaking to a child in comparison to adults conversing with each other. To do this, thirty infants (8;5-33 months) were “divided into three stages according to age; pre-lexical, single-word and early grammar” whilst the adult-directed speech corpuses included eighteen Hebrew-speaking parents of children at the same three stages of language development as in the Child-directed speech corpuses. Child-directed speech corpuses were collected during spontaneous activities at home; playtime, mealtime whilst adult-directed corpuses were collected from parent-experimenter interactions “including the parent watching a video, then being interviewed by the experimenter”. “Two hundred utterances of each sample were transcribed, coded and analysed qualitatively and quantitively respectively.” The results showed that in child-directed corpus, when speaking to infants of all ages, parents’ use of verbs and nouns was similar and significantly higher than their use of adjectives or adverbs whereas in the adult-directed corpus, verbs were the main lexical category.
Although this paper is well-researched and written clearly, however, a disadvantage is when experimenting adult-directed speech, the process was not as naturalistic. The child-directed speeches were collected during spontaneous activities at home, meaning that the outcome was done in a natural, unforceful way whereas, the parents were forced to watch a video, then being interviewed by the experimenter which meant parents knew that they were being watched, which therefore may change the way they talk. For both results to be spontaneous, the experimenter should allow parents to interact with their close family instead of interviewing them. Thus, this may make the experiment to not be fully accurate.
As children have a smaller range of vocabulary knowledge; there are fewer utterances per conversation, so caregivers tend to focus and stress on the key lexical items for the children to be able to remember it faster. This is known as vowel hyper articulation, “a speaker’s tendency to exaggerate the articulation of vowels in their speech, has been proposed to serve a didactic function in Child-directed speech.” (Santos, A.S. (2016)) “Such exaggerated intonation in parental speech is thought to serve several functions related to language development, including marking turn-taking episodes in mother-infant dialogue (Snow, 1977), helping the infant track and parse the speech stream, and acoustically highlighting new linguistic information. (Fernald & Simon, 1984) “As opposed to the average adult-directed speech (ADS), their voice becomes higher in pitch, it has a wider pitch range and the pitch contours are exaggerated (Naoi et al. 2012: 1735).” The reason why the use of verbs and nouns appeared significantly higher in Child-directed speech was because adjectives and adverbs are only terms that can further help to describe something whereas verbs and nouns are a common feature of everyday grammar. Therefore, caregivers teach children the basic rules of grammar to allow the infant in starting to become advanced once they go past the basic stage. When speaking to children, they tend to slower their speeches as well as pausing more between utterances and lexical items whereas the speech and articulation rate in adult-directed speeches tend to be faster. “It was found that children tend to prefer child-direct speech over adult-directed speech which shows in attention paid to the different speech registers”. (Cooper & Aslin, 1990). This shows that child-directed speech is simpler than adult-directed speech as during conversations and utterances, caregivers only focus on key terms whereas adults, having a broader knowledge of grammar and vocabulary, when conversing with each other, they tend to use a more complex set of grammatic rules that children would not understand.
The second study was by Association for Psychological Science whom also stressed that adult-directed speech is more complicated than child-directed speech. “The researchers first recorded twenty-two Japanese mothers talking to their children, (ages eighteen to twenty-four months) and an experimenter”. They then annotated the fourteen hours of speech, marking specific aspects of the speech including the beginnings and ends of consonants, vowels and phrases. “Next, the researchers applied a technique they had developed to measure acoustic similarity between any two syllables, for example, “pæ” and “bæ” as well as “pɒ” and “bɒ””. As the analysis is automated, they examined one hundred and eighteen most frequently used syllable contrasts that appear in both the child and adult-directed speeches. They discovered that mothers spoke slightly less clearly when talking to their child in comparison to when speaking to the experimenter. Alejandrina Cristia, a researcher at the Centre National de la Recherche Scientifique in Paris stated, “This finding is important because it challenges the widespread view that parents do and should hyperarticulate, using very robust data and an analysis based on a study of ten times as many syllable contrasts as previous work”. Furthermore, he also states that “our results suggest that, the fact that they are able to pick up sounds from input that is less clear than that used by adults with each other makes this accomplishment more remarkable”. Thus, this study also further emphasises that child-directed speech is simpler as caregivers tend to use a sing-song voice when communicating with the children which is why, caregivers are not clear when speaking to infants. Another common feature of child-directed speech is omitting past tenses and inflections. “In a recent systematic review of this literature, 85% of studies reported slower tempo and/or longer vowel duration; 92% found higher fundamental frequency (F0); and 82% documented larger vowel peripherality”. (Cristia, 2013).
The analysis of this experiment was automated which meant it was analysed by equipment’s which may not be fully believable as using technology to conduct analysis cannot be as accurate as doing it by hand. Thus, there may be mistakes that the technology may have not picked up which therefore makes the results of this experiment not fully believable. Also, the process of this experiment is vague and does not go into depth nor are they clear about the outcomes of the result.
One main reason why child-directed speech is simpler than adult’s speech is due to involving more pragmatic features; as children’s range of vocabulary is still very limited. During the early stages of childhood, caregivers tend to use body language and exaggerated gestures when communicating with the child to either mime a use of an object or an action. “The utterances are short, which lightens the memory load imposed by utterances”. (Traxler 2012: 338). Thus, this further emphasis the simplicity of child speeches compared to the adult as due to the wide knowledge of vocabulary, adults tend to use many adjectives and adverbs when communicating with one another. The reason why mother tends to speak less clearly to their children is because they believe that by speaking this way, children can acquire language more easily as it is simpler to understand than adult-directed speech.
The third study was conducted by Dodane, C.D., 2007 and he did an acoustic comparison of the vowel sounds in child and adult-directed speeches. He used five native speakers of British English and their babies, ages ranged from six to twenty-two months and conducted a naturalistic experiment in which the mothers were recorded at home by the father or a familiar person. “They had to read the same story to a familiar adult and to their child, which were recorded over two sessions for modalities to be clearly differentiated”. “Recordings were sampled at 22 kHz, 16 bits, mono and the data were segmented manually, and acoustic measurements of the first three formant frequencies were carried out with Praat, at the temporal mid-point for the corner vowels; /i/, /a/ and /u/. Overall, one hundred and eight-four vowels were made in adult-directed speech and one hundred and eighty-three vowels for child-directed speech. The results showed a “significant prosodic exaggeration from adult to child-directed speech”, with a slower speech rate found in the child-directed speeches; 4.14syllable per second in adult-directed speeches in comparison to the 3.26 syllable per second for child-directed speeches. They also discovered that the tones between the directed speeches are different with a four semi-tone higher pitch when parents are speaking to their children. The study observed that there was a downward shift of the vowel triangle in F1, from adult to child-directed speech, especially, the high vowel /i/ is more open, meaning there is a higher f1 value in child-directed speech. However, there are no differences found between /a/ and /u/. “On the front-back dimension (F2), there is a shift of the vowel triangle to the right of the vocalic space; /i/ is more backed, meaning that there is a lower F2 value and no significant effects for /a/ and /u/ are noticeable”. It has been discovered that the vowel area size increases as the child gets older and that the F1-F0 differences are more reduced in child rather than adult-directed speeches for the three vowels discussed above, /i/, /u/,and /a/. “this difference could be explained by an important increase of f0 from adult to child-direct speech as for both modalities, if the f1-f0 distance is greater for the low vowel /a/, this distance is much more reduced for the closed vowels /i/ and /u/ because of their lower F1.”
This image represent the vowel chart showing which part of the mouth are used to pronounce the certain vowel.
The reason why in child-directed speeches, the f1 value is higher is due to the caregiver carefully pronouncing and spelling the sound for the child to memorise. In adult-direct speech, f1 is lower due to the sound gliding through the mouth as vowels are sometimes used to elicit the endings of common words. As children are still unfamiliar with many speech sounds, they tend to acquire the vowel sounds the fastest as it is easier to pronounce and produce. “By highlighting the structure of speech, such as the differences between the vowels “a” and “o,” motherese helps babies translate a torrent of sound into meaningful units of language.” (Washington Post, 2018) Therefore, it further argues that child-directed speech is simpler as there are less grammatical rules than there are in adult-directed speech.
However, one disadvantage of this study is that it uses the front close vowel /i/ and the back-close vowel /u/ but it also includes the front-central open vowel /a/. Instead of using the front-central vowel /a/, it should use the central close vowel /ɨ/ as when pronouncing these three vowels, the mouth stays the same; it is slightly closed. Therefore, this would make the experiment to be more interesting and fair.
Conclusion
In conclusion, child-directed speech is simpler than adult-directed speech due to the basic forms of grammar, pragmatic, morphological uses as well as focusing on specific key words to ensure children know which words to learn. Furthermore, instead of using language to converse to infants, many caregivers tend to make use of body movements and gestures to imply an action. Therefore, infants learn quicker by using child instead of adult-directed speech.