Kathleen Currie Hall 9 May 2005 Notes on: Koopmans-van Beinum, Florien J., Clement, Chris J., & van den Dikkenberg-Pot, Ineke. (2001). Babbling and the lack of auditory speech perception: A matter of coordination? Developmental Science, 4(1), 61-70. Summary: In this article, the authors attempt to address the question of how much of a role auditory feedback plays in the development of speech production. Their strategy is to compare the productions of hearing-impaired and normal-hearing infants to determine what type of productions seem to be independent of auditory feedback (i.e., physiological, etc.) and what type seem to require such feedback. Details: 1. They describe all the productions using a "sensorimotor" classification system, which they claim is independent of any language-specific factors. Based on the soure-filter theory of speech production, it classifies all productions in terms of phonation type (the source: interrupted or not, varied or not) and articulation type (the filter: none, one articulator, two). 2. They compared five normal-hearing infants and five hearing-impaired infants, using utterances from recordings made by the parents every two weeks or every month for the first two years. 3. They found that NH infants produced more utterances that combined phonation and articulatory movements, while HI infants produced more utterances that just involved phonation, without articulatory movements. They conclude that the coordination of phonation and articulation is crucially linked with having auditory feedback of one's own productions. Questions: 1. Can we go over examples of how they would actually implement this language-independent classificatory system? Does it actually work? Is it really as easy to implement as they imply? How reliable is it? etc. . . . (how do they determine presence of articulatory movement in the absence of phonation using just audio recordings?) 2. Relatedly -- what do they mean by determining "syllable structure" or place and manner -- how do they possibly do this in a language-independent way? 3. I know they say that there didn't seem to be an effect of any of the vast differences among the HI infants in terms of hearing aid use or communication type, but this seems implausible. Is it just the sample size? How are they really showing anything about the role of auditory feedback if one of the kids didn't use a hearing aid while one had one from the age of 2 months? 4. Relatedly -- the one infant who was hearing impaired but did start babbling at a normal time (7.5 months as opposed to 18 months) -- they say that he "could obviously make use of a hearing residue . . . " (p. 69). But doesn't this make their argument circular? There is overall a difference between the NH and the HI kids, which they attribute to auditory feedback. So when that difference isn't present, clearly there was not a difference in auditory feedback . . . but maybe the original difference wasn't due to auitory feedback in the first place, and their sample is just a fluke (especially since some of the infants had hearing aids and might have had aud. feedback). I wonder which infant it was that was HI but started babbling "on time" . . . why don't they tell us? From: ejkong@ling.ohio-state.edu The study of comparing normal-hearing and hearing-impaired infants' production at their pre-word stage shows that HI babies are bad at coordinating phonation and articuation, indicating the auditory feedback as well as the physiological development is playing an important role in the speech developmental process. From: nagar@ling.ohio-state.edu This study talks about the stages that children go through when leaning a language. They discuss early vocalization in kids and influence that auditory input as on this. They study the language learning process of deaf children and hearing children. They use a ?source-filter? model which means that the larynx is treated as the source of sound and provide a matrix which shows the ways in which types of phonation can be divided. The experimenters record the phonation of babies as soon as they are believed to be producing sounds. Results are compared between hearing and hearing- challenged children and the impact of auditory input is considered to be of consequence for learning language and vocalization. Hearing impaired children had problems with certain phonation types more than other phonation types which hint at a connection between different articulatory movements with phonation types. From: LAURA SLOCUM 1) In their intro the authors seem to discrediting spontaneous vocalizations such as crying/laughing/etc. Why? I understand that for the purposes of the current study these are not relevant. However, do these fit into (or not) comparison discussions re: HI/non-HI children's development, in general? 2) How are they defining "motor functions" on page 64 of this study? What do they mean by "other motor functions"? What do they consider normative in this area for the first year of life? 3) All of the deaf children had hearing aide, although "not all of the children used them regularly during the first year." Was there any control comparison for children who used them regularly or not? Junko Davis The study shows that auditory perception and feedback are necessary for the coordination of the movements of the phonatory and articulatory systems for speech development based on the comparison between deaf infants and normally hearing in fants. - It is somewhat surprising that there was no significant difference in the results between the better hearing HI infants and the worse hearing ones. I wonder whether or not the results would stay the same if the size of the subject pool w ere larger, although it seems that it is extremely difficult to find appropriate subjects to fit in the category. - Could some of the deaf infants in the study whose language method is either TC or NGT/TC be babbling in hands in addition to the vocal babbling at the time? What would be the relationship between the amount of vocal babbling and the bab bling in hands? (canceling out or enhancing each other?) From: HELENA RIHA On p. 62, the authors describe the sensorimotor description system used in their study to classify vocalizations made by deaf and hearing children. This is an innovative system quite different from the one used by Kuhl and Meltzoff (1996), in which infant vowel vocalizations are characterized acoustically in terms of first and second formant frequencies. Could we talk more about the sensorimotor description system in class? The authors' characterization of infant vocalizations in a simple manner in terms of phonation type and articulation type seems more in line with the natural units of representation proposed by Beckman and Edwards (2000) (Fig. 14.1, p. 211). Looking at the sound production results for deaf and hearing children in Figures 2 and 3, I wonder how those results relate to Kuhl and Meltzoff?s findings about the importance of vocal imitation. In particular, I thought about a way to link the finding that deaf children engage in more ?uninterrupted and interrupted phonation without any articulatory movement? than hearing children with Kuhl and Meltzoff?s view of vocal imitation. My guess is that even though deaf children can't hear, they may still feel the rhythmic sensations of ambient language (and their own vocalizations) and that they may try to imitate the rhythm of language through phonation. Since they do not hear articulations, however, they do not try to imitate them. From: Fangfang Li this paper investigates the role of auditory feedback during the course of early language development by comparing normal hearing children with hearing-impaired children. they found that HI children, like their NH peers starts to make repetitive and rhythmic phonatory movement around the typical "babbling" stage, but lack the rhythmic articulatory movements evident in the canonical babbling of NH children. questions: it is interesting to note in Figure 2 that deaf children starts to peak in their movement of the two systems like normal children do around 5.5-7.5 months, but seems to decrease their articulatory movements later on. this result seems partly counter-intuitive to me since to deaf children, although auditory feedback is lacking, they can still observe other's articulatory movement (like lips), and therefore can make similar sounds. so the question is why they end up with stopping manipulating the articulatory gestures and still continue or even increase phonatory movement? what is the reason for this preference? From: Kirk Baker Result: HI less often produce articulation; phonation is variable. NH phonation combined with articulation. -I need examples of their classification types. too unfamiliar for me to understand very well what they're saying. From: ASIMINA SYRIKA The article discusses differences in the canonical babbling of infants with normal hearing (NH) and profoundly hearing impaired (HI). The topic is very interest ing and touches upon an area where further research is called for. The article was in part an answer to a question I had previously stated about the babbling of deaf infants. The only objection I have to the writers' conclusion that auditory feedback is the necessary requirement for the production of canonical babbling is that they seem to take for granted that oral speech is critical to the language acquisition process. Manual babbling that occurs in infants exposed to sign language is reported to present many similarities to oral babbling. I personally don't see why we should exclude manual babbling from being canonical simply because sign languages are based on visual-tactile rather than auditory feedback. I was also wondering whether the different intervention programs that the HI infants of the study participated in had different effects on their auditory perception and production. The writers mention that some infants had hearing aids, some were raised with total communication, some with sign language and some others with the oral approach. These are very different methods and each may have a different impact on the language development of the child. I believe that there should have been a better subject matching rather than including HI infants from so many different categories. I'm also not sure I understand what the writers mean with interrupted vs. uninterrupted and variable interrupted vs. variable uninterrupted phonation. Last but not least, 'Is there oral babbling in sign language? If an infant is only exposed to sign from birth will he/she still babble orally?' 'If deaf infants are diagnosed early and have hearing aids soon doesn't that increase their chances to babble and produce speech at roughly the same rate and time as typically-developing children?