Marklund, E. , Schwarz, I. & Lacerda, F.
Stockholm Babylab, Phonetics Lab, Department of Linguistics, Stockholm University
During the first year of life, infants? ability to discriminate non-native speech contrasts attenuates, whereas their ability to discriminate native contrasts improves. This transition reflects the development of speech sound categori¬zation, and is hypothesized to be modulated by exposure to spoken language. The ERP mismatch response has been used to quantify discrimination ability in infants, and its amplitude has been shown to be sensitive to amount of speech exposure on group level (Rivera-Gaxiola et al., 2011). In the present ERP-study, the difference in mismatch response amplitudes for spoken vowels and for spectrally rotated vowels, quantifies categorization in 8-month-old infants (N=15, 7 girls). This categorization measure was tested for correlation with infants? daily exposure to male speech, female speech, and the sum of male and female speech, as measured by all-day home recordings and analyzed using LENA software. A positive correlation was found between the categorization measure and total amount of daily speech exposure (r = .526, p = .044). The present study is the first to report a relation between speech exposure and speech sound categorization in infants on subject level, and the first to compensate for the acoustic part of the mismatch response in this context.