Aizuchi

In the Japanese language, aizuchi (相槌 or あいづち, ) are interjections during a conversation that indicate the listener is paying attention or understands the speaker (backchanneling). In linguistic terms, these are a form of phatic expression. Aizuchi are considered reassuring to the speaker, indicating that the listener is active and involved in the discussion.

Examples
Common aizuchi include: These have a similar function to English "yeah", "yup", "OK", "really?", "uh-huh", "oh", and so on.
 * hai (はい), ee (ええ), or un (うん)
 * sō desu ne (そうですね)
 * sō desu ka (そうですか)
 * hontō (本当), hontō ni (本当に), maji (マジ), or (in Kansai) honma (本真)
 * naruhodo (なるほど)
 * nodding

Aizuchi are frequently misinterpreted by non-native speakers as the listener showing agreement and approval. Business relations in particular can be hampered by non-native speakers assuming that their Japanese counterparts have been agreeing to their suggestions all along, especially with hai (はい), when the native Japanese speaker meant only that they follow or understand the suggestions – "got it", not "agreed".

Aizuchi can also take the form of so-called echo questions, which consist of a noun plus desu ka (ですか). After Speaker A asks a question, Speaker B may repeat a key noun followed by desu ka to confirm what Speaker A was talking about or simply to keep communication open while Speaker B thinks of an answer. A rough English analog would be "A ..., you say?", as in: "So I bought this new car"; reply: "A car, you say?".