Josiane Bertoncini

A precursor of language acquisition in young infants

Abstract Four-day-old French and 2-month-old American infants distinguish utterances in their native languages from those of another language. In contrast, neither group gave evidence of distinguishing utterances from two foreign languages. A series of control experiments confirmed that the ability to distinguish utterances from two different languages appears to depend upon some familiarity with at least one of the two languages. Finally, two experiments with low-pass-filtered versions of the samples replicated the main findings of discrimination of the native language utterances. These latter results suggest that the basis for classifying utterances from the native language may be provided by prosodic cues.

Language Discrimination by Newborns: Toward an Understanding of the Role of Rhythm

Three experiments investigated the ability of French newborns to discriminate between sets of sentences in different foreign languages. The sentences were low-pass filtered to reduce segmental information while sparing prosodic information. Infants discriminated between stress-timed English and mora-timed Japanese (Experiment 1) but failed to discriminate between stress-timed English and stress-timed Dutch (Experiment 2). In Experiment 3, infants heard different combinations of sentences from English, Dutch, Spanish, and Italian. Discrimination was observed only when English and Dutch sentences were contrasted with Spanish and Italian sentences. These results suggest that newborns use prosodic and, more specifically, rhythmic information to classify utterances into broad language classes defined according to global rhythmic properties. Implications of this for the acquisition of the rhythmic properties of the native language are discussed.

Infant Recognition of Mother's Voice

Each of a group of one-month-old infants was reinforced, contingent upon nonnutritive sucking, with its mothers voice and the voice of a stranger. In this experiment, two conditions were applied. Under the first, the mothers speech was aimed at communicating with the infant, while, under the second, the mothers speech lacked prosodic and intonational aspects of normal speech. It was shown that infants will suck more for their mothers voices under the intonated condition only. It was concluded that a young infant prefers its own mothers voice provided the mother speaks normally.

Do infants perceive word boundaries? An empirical study of the bootstrapping of lexical acquisition

Babies, like adults, hear mostly continuous speech. Unlike adults, however, they are not acquainted with the words that constitute the utterances; yet in order to construct representations for words, they have to retrieve them from the speech wave. Given the apparent lack of obvious cues to word boundaries (such as pauses between words), this is not a trivial problem. Among the several mechanisms that could be explored to solve this bootstrapping problem for lexical acquisition, a tentative but reasonable one posits the existence of some cues (other than silence) that signal word boundaries. In order to test this hypothesis, infants were used as informants in our experiments. It was hypothesized that if word boundary cues exist, and if infants are to use them in the course of language acquisition, then they should at least perceive these cues. As a consequence, infants should be able to discriminate sequences that contain a word boundary from those that do not. A number of bisyllabic stimuli were extracted either from within French words (e.g., mati in mathématicien), or from between words (e.g., mati in panorama typique). Three-day-old infants were tested with a non-nutritive sucking paradigm, and the results of two experiments suggest that infants can discriminate between items that contain a word boundary and items that do not. It is therefore conceivable that newborns are already sensitive to cues that correlate with word boundaries. This result lends plausibility to the hypothesis that infants might use word boundary cues during lexical acquisition.

Before and after the vocabulary spurt: two modes of word acquisition?

This paper focuses on early lexical development, and especially the period around 18 months known as the vocabulary spurt. We first propose that this period corresponds to a shift from an associationist to a referential lexical acquisition mechanism following the developmental coupling of specific pre-linguistic and cognitive abilities. This latter mechanism would allow the acquisition of genuine words, i.e. links between phonetically specified sound patterns and object categories. We then review the literature on early lexical acquisition by typically developing infants and infants with Down and Williams syndrome, and report some data that were recently collected on this issue. We conclude that the data so far are congruent with our proposal, but because they remain insufficient, we propose some future research that focuses on the relation between pre-linguistic and cognitive developments.

An investigation of young infants' perceptual representations of speech sounds.

The present study examined the ability of newborns and 2-month-olds to detect phonetic differences between syllables. By relying on the modified high-amplitude sucking procedure, which did not permit the infants to use a simple same-different response, the present experiments tapped the perceptual representations of the speech sounds. Infants as young as a few days old displayed some capacity to represent differences in a set of syllables varying in their phonetic composition, although there was no convincing evidence that their representations were structured in terms of phonetic segments. Finally, evidence of developmental changes in speech processing were noted for the first time with infants in this age range. The change noted was a tendency from global toward more specific representations on the part of the older infants.

Discrimination of pitch contours by neonates

With the high-amplitude sucking procedure, newborns were presented with two lists of phonetically varied Japanese words differing in pitch contour. Discrimination of the lists was found, thus indicating that newborns are able to extract pitch contour information at the word level.

Syllables as units in infant speech perception

The aim of the research we have carried out is to assess the role of the syllable in the processing of speech in the very young infant. We used three kinds of stimuli: syllabic, non-syllabic and syllabic-synthetic sequences. These were presented to infants who were less than 2 months old in an habituation-dishabituation paradigm. Results indicate that the syllable-like stimuli are discriminated better than the non-syllable-like stimuli even though the physical change from the habituation to the dishabituation stimuli was always the same. We interpret our results as favoring a view according to which the syllable is the natural unit of speech segmentation and processing.

Dichotic perception and laterality in neonates

Groups of 4-day-old neonates were tested for dichotic discrimination and ear differences with the High-Amplitude-Sucking procedure. In the first experiment, dichotic speech discrimination was attested by comparison with a control group. Furthermore, among those subjects who showed a substantial recovery of sucking response at least after one of the two syllable changes, it was observed that significantly more subjects manifested a stronger reaction to a right-ear change than to a left-ear change. In the second experiment, 4-day-old neonates were tested on syllable and music timbre discrimination. The significant Stimulus Type x Ear interaction observed suggests perceptual asymmetries indicative of very precocious brain specialization.

Viewing The Development of Speech Perception As An Innately Guided Learning Process

The present paper examines the issue of how speech sounds may be treated by infants as special signals relative to other kinds of acoustic stimuli. Consideration is given to the view that the mechanisms underlying the infants perception of speech are specialized for this purpose. Some of the difficulties of providing definitive evidence for or against this position are noted. Then the thesis is advanced that special processing of speech may lie in the inherent salience which such sounds have for infants. in particular, it is suggested that the development of speech perception follows the course of an innately guided learning process. One key assumption of this view is that speech sounds may be more apt to attract attention or have a higher priority for further processing than other types of acoustic signals. Recent evidence from a number of new paradigms for studying infant speech perception is reviewed in light of this position. The paper concludes with a discussion of how findings concerning the development of speech perception during the first year of life fit with the innately guided learning view.