haa...

this "h" pronounced half nazal in this expression, not a regular h

haaa

when your voice goes down it means "i didnt get it before but now i understand" it may be used in everywhere.

haa

when your voice goes up it means "what did you say, i didnt get it?" this version is considered a bit rude. it may be used to friends only. oherwise you may get a warning" ha değil efendim"