The acquisition of Japanese backchanneling behavior: Observing the emergence of aizuchi in a Japanese boy

Japanese backchannel signals (aizuchi) can be divided into two types, utterance-internal and utterance-final. While sentence-final aizuchi are comparable to English backchannel signals like “I see” or “really”, the utterance-internal aizuchi signal only continuation and understanding (“I listen”), but never agreement or empathy. Aizuchi exchange consists of a complementary pair of the aizuchi invitation by the speaker and the actual aizuchi delivered by the listener. Our present study focuses on the acquisition of aizuchi in a boy aged 1;5 to 3;1. We observed a developmental delay between utterance-final aizuchi, and utterance-internal aizuchi, which appeared about 6 months later than the utterance-final aizuchi. Also the invitations for utterance-final aizuchi appeared earlier than the invitations for utterance-internal aizuchi. We also observed an overuse of aizuchi invitations, while the number of aizuchi delivered was comparatively low. This overuse can be explained by the pragmatic value of aizuchi invitations which can be ideal for negotiating support for one's turn and gaining time in order to organize thoughts into a well-formed sentence.