In English conversations, when I listen to someone speak, I have a habit of intermittently uttering "mhm" just to let the other person know I'm listening to what he/she is saying. Is there a Japanese equivalent of this? I'm thinking of "はい", but I don't know if it will come off as being too stiff.
They're called aizuchi. はい is certainly one. うん is the more casual option. Wikipedia has the following:
In the Japanese language, Aizuchi (Japanese: 相槌 or あいづち, IPA: [aizu͍t͡ɕi]) are the frequent interjections during a conversation that indicate the listener is paying attention or understands the speaker. 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.
Aizuchi are frequently misinterpreted by non-native speakers as the listener showing agreement or fully comprehending what is being said.
Common aizuchi include:
- hai (はい), ee (ええ), or un (うん) (yes, with varying degrees of formality)
- sō desu ne (そうですね) (I see.)
- sō desu ka (そうですか) (is that so?)
- hontō (本当), hontō ni (本当に), maji (マジ), or (in Kansai) honma (本真) (really)
- naruhodo (なるほど) (I see, that's right)
These can be compared to English "yeah, yeah", "yeah, ok", "got it", "yep", "uhuh" or "go on", but are more pronounced and important in Japanese.
yes, one way of indicating that you are listening and the other person should continue talking is by saying "はい". However your habit of saying "mhm" would not be so out of place, actually. There is a Japanese equivalent in the ん sound. It's less "courteous" than saying "はい", but it is a typical "I'm listening" noise.
annnnnnd @leocreatini beat me to it in the comments :P