Infants' sensitivity to nonadjacent vowel dependencies: The case of vowel harmony in Hungarian.

Vowel harmony is a linguistic phenomenon whereby vowels within a word share one or several of their phonological features, constituting a nonadjacent, and thus challenging, dependency to learn. It can be found in a large number of agglutinating languages, such as Hungarian and Turkish, and it may apply both at the lexical level (i.e., within word stems) and at the morphological level (i.e., between stems and their affixes). Thus, it might affect both lexical and morphological development in infants whose native language has vowel harmony. The current study asked at what age infants learning an irregular harmonic language, Hungarian, become sensitive to vowel harmony within word stems. In a head-turn preference study, 13-month-old, but not 10-month-old, Hungarian-learning infants preferred listening to nonharmonic VCV (vowel-consonant-vowel) pseudowords over vowel-harmonic ones. A control experiment with 13-month-olds exposed to French, a nonharmonic language, showed no listening preference for either of the sequences, suggesting that this finding cannot be explained by a universal preference for nonharmonic sequences but rather reflects language-specific knowledge emerging between 10 and 13 months of age. We discuss the implications of this finding for morphological and lexical learning.