Developmental changes in perception of nonnative vowel contrasts.

TLDR

The study used a head‑turn procedure to test English‑learning infants (6–8 and 10–12 months) on two German vowel contrasts. Younger infants (6–8 months) discriminated the vowel contrasts better than older infants, yet their performance was lower than that seen for nonnative consonants; a separate habituation experiment showed 4‑month‑olds could discriminate both vowels while 6‑month‑olds could not, indicating a shift from language‑general to language‑specific processing that occurs earlier for vowels than for consonants.

Abstract

Discrimination of 2 German vowel contrasts was examined in English-learning infants of 6-8 and 10-12 months of age using a head turn procedure. The younger infants were better able than the older infants to discriminate the nonnative contrasts, but performance at 6-8 months was below levels that have been reported for nonnative consonant contrasts. A 2nd experiment using a habituation looking procedure showed that 4-month-old infants discriminated both German vowel contrasts, but the 6-month-olds could not. The findings are consistent with previous consonant work, revealing a shift from a language-general toward a language-specific pattern during the 1st year of life. However, that shift begins earlier in development for vowels than for consonants.