Newborn infants differently process adult directed and infant directed speech.

Infant directed speech (IDS) may serve important functions in language acquisition and in adult-infant communication. The processing of IDS evolves during the first years of life. In order to serve as an effective tool of language acquisition, already very young infants should be able to distinguish IDS from adult directed speech (ADS). We tested whether the ability to discriminate these two speech registers is functional in neonates, by recording EEG from 98 newborn infants in response to Hungarian words naturally spoken in the IDS and the ADS register. Words presented in the ADS register elicited a centro-parietal slow positivity in the 200-600 ms time window whereas words in IDS register elicited a small frontal negativity in the 700-900 ms time window. We conclude that newborn infants differentiate natural speech sounds based on speech register.