What is the impact of age of second language acquisition on the production of consonants and vowels among childhood bilinguals?

Abstract

This study investigated bilinguals’ ability to produce language-specific acoustic values for consonants and vowels that are highly similar across the two languages. To investigate this ability, we targeted early bilinguals who had acquired two languages before the age of 12 and continued to use both languages on a daily basis. These adult bilinguals were separated into two groups: simultaneous bilinguals (or nearly so) who acquired both languages by their third year, and sequential bilinguals who acquired their second language between the ages of 8 and 12 years. Their speech production was studied through an acoustic analysis of stop consonants (voice onset time) and vowels (formant structure). Despite the differences in age of acquisition, these bilinguals used both languages on a regular basis at work and at home and were very proficient in both languages. In contrast to other early bilinguals who undergo a change in language dominance from their first language to their second, the participants in this study maintained relatively balanced abilities in both languages. This study revealed that childhood bilinguals can maintain contrasts across their two languages, even for very similar phonemes.