Backchannel

In conversation, we frequently use “hmm”, “mm-hm”, “uh-huh”, “yeah”, etc. when listening to a speaker. In linguistics, these responses are called “backchanneling”, “backchannel responses”¹, or even “aizuchi”² (the Romaji transcription of あいづち).

Backchanneling often functions as phatic expressions, which themselves do not carry much information, but serve to facilitate conversation. The frequency of their use varies from contry to country. For instance, it is said that we Japanese use aizuchi more often than Americans.

Also, there are subtle differences in their meanings depending on the culture. One of the basic Japanese aizuchi うん is often used to simply mean “I’m listening”, while the English backchanneling “mm-hm” or “uh-huh” specifically implies that “I’m yielding the conversational turn to you”. Therefore, Japanese people need to be careful not to use them quite often, especially when the speaker has just finished talking.

By the way, the word “backchannel” itself literally means “A secondary channel”. In other contexts than linguistics, it can refer to the following two things: “A secondary channel of water” and “in politics, a means of communication which circumvents official channels”.