Abstract processing of syllabic structures in early infancy.

Syllables are one of the fundamental building blocks of early language acquisition. From birth onwards, infants preferentially segment, process and represent the speech into syllable-sized units, raising the question of what type of computations infants are able to perform on these perceptual units. Syllables are abstract units structured in a way that allows grouping phonemes into sequences. The goal of this research was to investigate 4-to-5-month-old infants' ability to encode the internal structure of syllables, at a target age when the language system is not yet specialized on the sounds and the phonotactics of native languages. We conducted two experiments in which infants were first familiarized to lists of syllables implementing either CVC (consonant-vowel-consonant) or CCV (consonant-consonant-vowel) structures, then presented with new syllables implementing both structures at test. Experiments differ in the degree of phonological similarity between the materials used at familiarization and test. Results show that infants were able to differentiate syllabic structures at test, even when test syllables were implemented by combinations of phonemes that infants did not hear before. Only infants familiarized with CVC syllables discriminated the structures at test, pointing to a processing advantage for CVC over CCV structures. This research shows that, in addition to preferentially processing the speech into syllable-sized units, during the first months of life, infants are also capable of performing fine-grained computations within such units.

Before perceptual narrowing: The emergence of the native sounds of language.

The present study investigates the precursors of representations of phonemes in 4.5-month-olds. The emergence of phonemes has been mainly studied within the framework of perceptual narrowing, that is, infants tuning to their native language and losing sensitivity to non-native speech. One of the mechanisms behind this phenomenon is distributional learning. In this article, we tested the preference of 4.5-month-old infants using lists of pseudowords that resemble the vowel distribution of the native or a non-native language. We found that infants prefer listening to the lists mirroring the native language. The results suggest that infants can extract vowel information from novel stimuli, and they can map it on pre-existing knowledge on vowels that leads to a preference for the native lists.

The ontogeny of early language discrimination: Beyond rhythm.

Infants can discriminate languages that belong to different rhythmic classes at birth. The ability to perform within-class discrimination emerges around the fifth month of life. The cues that infants use to discriminate between prosodically close languages remain elusive. Segmental information could be a potential cue, since infants notice vowel mispronunciations of their names, show the first signs of word recognition and the first signs of perceptual narrowing for vowels around 6 months of age. If infants have in place some proto-segmental information, most likely it is about vowels. Another potential cue infants may use to discriminate languages is intonation. We tested participants using sentences in Eastern Catalan, Western Catalan and Spanish. The two Catalan dialects and Spanish belong to the same rhythmic class, they are syllable-timed, but they differ in terms of vowel distribution, given that only Eastern Catalan has vocalic reduction. The vowel distributions of Western Catalan and Spanish are more comparable. However, they differ in terms of their intonational patterns. In Experiment 1, we tested the ability of 4.5-month-old infants learning Eastern Catalan and/or Spanish to discriminate between sentences in Eastern and Western Catalan and in Experiment 2 their ability to discriminate between sentences in Western Catalan and Spanish. In order to disentangle the contribution of segmental and suprasegmental information, we also tested infants using low-pass filtered sentences in the two dialects (Experiment 3) and low-pass filtered sentences in Western Catalan and Spanish (Experiment 4). Infants discriminated the two Catalan dialects only when the stimuli were natural sentences, whereas they were able to discriminate between Western Catalan and Spanish when the stimuli were either natural or low-pass filtered sentences. The research also provides evidence of equivalent language discrimination abilities in infants growing up in monolingual and bilingual environments.