Infants show a facilitation effect for native language phonetic perception between 6 and 12 months.

Patterns of developmental change in phonetic perception are critical to theory development. Many previous studies document a decline in nonnative phonetic perception between 6 and 12 months of age. However, much less experimental attention has been paid to developmental change in native-language phonetic perception over the same time period.

Differences in glottal opening pattern between Tokyo and Osaka dialect speakers: factors contributing to vowel devoicing.

In Japanese, high vowels /i/ and /u/ are often devoiced when they are preceded and followed by voiceless consonants. The phenomenon is called vowel devoicing. The frequency of its occurrence is high in dialects of eastern Japan including standard (Tokyo) Japanese and low in dialects of western Japan including Osaka dialect.