There are a lot of filler words that crop up in non-scripted conversation.
うん or ああ (Un or Ah): “Yeah”
あれ？ (Are): “Huh” or “What the?”
ふーん (Fuun): “Hmm”
えーと (Ehto): “Umm”
なんか (Nanka): “Like”
だな (Dana): “I guess so.” or “Yeah”
だよな (Dayona): “Makes sense.” or “Of course.”
すごい (Sugoi): “Wow.”
None of these are direct translations; I am just trying to come up with what an English speaker would say in the same way. In Japanese, it is considered rude to just listen to somebody silently, so one will often chime in with words of agreement or understanding. Words used to chime in like this are called “aizuchi.”
Here’s a Wikipedia page on aizuchi.
