Infant-directed speech supports phonetic category learning in English and Japanese.
Across the first year of life, infants show decreased sensitivity to phonetic differences not used in the native language [Werker, J. F., & Tees, R. C. (1984). Cross-language speech perception: evidence for perceptual reorganization during the first year of life. Infant Behaviour and Development, 7, 49-63]. In an artificial language learning manipulation, Maye, Werker, and Gerken [Maye, J., Werker, J. F., & Gerken, L. (2002). Infant sensitivity to distributional information can affect phonetic discrimination. Cognition, 82(3), B101-B111] found that infants change their speech sound categories as a function of the distributional properties of the input. For such a distributional learning mechanism to be functional, however, it is essential that the input speech contain distributional cues to support such perceptual learning. To test this, we recorded Japanese and English mothers teaching words to their infants. Acoustic analyses revealed language-specific differences in the distributions of the cues used by mothers (or cues present in the input) to distinguish the vowels. The robust availability of these cues in maternal speech adds support to the hypothesis that distributional learning is an important mechanism whereby infants establish native language phonetic categories.
Werker
Janet F
JF
Department of Psychology, The University of British Columbia, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4. jwerker@psych.ubc.ca
Pons
Ferran
F
Dietrich
Christiane
C
Kajikawa
Sachiyo
S
Fais
Laurel
L
Amano
Shigeaki
S
D002170:Canada; D006801:Humans; D007223:Infant; D007564:Japan; D010700:Phonetics; D013067:Speech Perception; D014705:Verbal Behavior; D014706:Verbal Learning