Abstract: Researches about speech perception in infancy indicate 1-4-month-old infants can discriminate most phonetic category contrast, including native category contrasts and nonnative category contrasts. With more exposure to native-language, the effects of native-language phonology on infant speech perception emerge: perception of consonants evidences the increasing sensitivity to native phonetic category boundaries and the decreasing sensitivity to nonnative category boundaries, the nonnative phonetic category being assimilated with the native category, and perception of native vowels exhibits “the perceptual magnet effect”. These facts indicate infants come to acquire native-language phonemic category, the order of native category acquisition possibly depends on some factors, such as the acoustic characteristics and the frequency of occurrence of category example

Key words: speech perception, infancy, consonants, vowels