Infants prefer native language to foreign language soon after their birth. This experiment aimed to determine whether infants can detect the phonological differences between a native dialect and an unfamiliar dialect, even though both dialects belong to the same language. The subjects are 43 infants, 5 to 8-months-old. All infants came from families speaking Eastern Japanese dialect only, and had had little exposure to Western Japanese dialect. Preferential listening time toward the Eastern and Western dialect was measured by me Head Turn Preference Procedure. The result demonstrated that 8-month-old infants showed greater preference to the native Eastern dialect than the unfamiliar Western dialect, whereas 5,6,7-month-old infants didn't show any significant difference in their listening time. This fact suggests that 8-month-old infants can detect the difference of these dialects, and pay more attention to a native dialect than to an unfamiliar one.
