Hyperboreus:I think something goes seriously wrong if you have to look up emotional and onomatopoetic exclamations in a dictionary.

Why? Ask speakers of six different languages what sound a bell makes, or a rooster makes when it crows, and you'll get at least six different answers. Sometimes an onomapoetic sound is going to be obvious, sometimes not. And if for instance you've never encountered the exclamation "Bis! Bis!" before, how are you supposed to know what it means without looking it up? It's very different from the "Encore!" we'd use in English or French, or the meaning of "bis" in German (until).

Hyperboreus:Sed kiu definas kion signifas ĉiu el tiuj ĉi vortoj?
Kiel vi interpretus "ba!"?

It is quite simple: you just look up in PIV:

ba!

I'm really suprised no one has mentioned one of my favorites: fek!