A wealth of behavioral research suggests that infants become increasingly specialized in their native dialect/language in infancy. In contrast, few studies document how this early specialization is reflected in neural activation, most of which have compared familiar and unfamiliar languages, and none focused on different dialects. This study aimed to fill that gap, focusing on cerebral activation in temporal areas, as measured with near infrared spectroscopy. Audiovisual infant‐directed speech was recorded from talkers of either Parisian or Quebecois French. These videos were presented to 5‐month‐old Parisian infants in blocks within which videos from two talkers alternated in one of two ways. In pure blocks, both talkers were either Parisian (pure‐familiar) or Quebecois (pure‐unfamiliar). In mixed blocks, the two talkers had different dialects. A robust and mostly bilateral activation was found for both mixed and pure blocks. Follow‐up comparisons revealed a stronger activation for mixed blocks than for pure ones, and a trend for more activation in response to the unfamiliar dialect than to the familiar one. These findings are congruent with behavioral studies showing early sensitivity to dialects and extend the brain imaging literature on early neural attunement to the language as spoken in the infant’s environment.