Relating moms Apostrophe productions of infant directed speech with their babies Apostrophe ability to discriminate speech: A brain measure study with monolingual and bilingual infants

Abstract

We report the benefit of Infant Directed Speech (IDS) on speech discrimination in 11- and 14 month-old monolingual (N = 16) and bilingual infants (N = 14). Mothers were instructed to read a booklet to their infants that contained sentences with target words (e.g., park, tear, bark, deer, etc.) at least once a day for four days. This activity was recorded by the LENA digital recorder that the infants were carrying around as they went about their lives. IDS was defined as the mothers' voice-onset time (VOT) durations when reading the booklet at home to their infants. Adult Directed Speech Mothers' IDS productions were correlated with their infants' brain responses associated with speech discrimination (Mismatch Negativity Response or MMR). The results showed that mothers' IDS correlated positively with the bilingual infants' positive-MMR and the monolingual infants' negative-MMR. Bilinguals' positive-MMR is interpreted as a less mature brain response since the positivity declines with age and a negative-MMR (adult-like) emerges later in development. These results show that even though the monolinguals and the bilinguals are at different developmental stages—as demonstrated by their MMRs— both monolingual and bilingual infants benefit from IDS to learn the sounds of their native language(s).