Linking early phonolexical acquisition and later vocabulary development – CbiasPrediction

Language acquisition is a key aspect of human development, predicting later school achievements. Phonology and the lexicon both start being acquired early, around 6 months of age. In this project, we test the proposal that a crucial milestone in language acquisition is reached when infants discover which sounds (consonants versus vowels) are more important at the lexical level in their native language, leading to an acceleration of subsequent vocabulary development. This project originates in the fact that across many languages, including English and French, consonants are more important at the lexical level than vowels (called consonant bias, or C-bias). However, previous developmental and crosslinguistic work showed that this C-bias is acquired, and can lead to a consonant or vowel bias depending on the properties of the native language (the Sound-of-Words bias). Here, we investigate the acquisition of the C-bias in French in three different developmental populations (monolingual infants born at term; bilingual infants born at term; monolingual preterms), tested at the age of 12 months, when they start saying their first words. Using the high-density event-related potential (ERP) technique, we will first specify the brain mechanisms underlying this bias. Second, in a longitudinal follow-up, we will use parental questionnaires and standardized tests to test the prediction that the acquisition of this bias accelerates subsequent vocabulary development. We will also evaluate quantity and quality of the linguistic input addressed to the infants at 12 months to determine their impact on the C-bias and later linguistic development. A better understanding of this Sound-of-Words bias will inform us on key theoretical issues in developmental psychology, such as the articulation of nature and nurture in language development, the integrative acquisition of different linguistic levels, and the cascading nature of acquisitions over time. Applied implications include setting up targeted remediation and education procedures.