- maybe = vielleicht

- probably = wahrscheinlich

- definitely = bestimmt

But a big part of the gap between being able to speak in a language and being able to comprehend a language is that there are often plenty of ways to communicate/translate the same concept. It's much easier for a learner to say "vielleicht" every time they mean to indicate "maybe" than it is for a learner to learn that "vielleicht", "eventuell", "möglicherweise", etc. all basically map to the concept of "maybe" (which of course conceptually maps to its own set of English words - "maybe", but also "perhaps", "possibly", etc.).

It gets even hairier because word choice is highly culture-bound and the semantics are not guaranteed to be the same as the top dictionary definition. "Could you maybe take a look at this?" is not really asking someone to "maybe" take a look, the asker definitely wants them to take a look, it's just a construction that carries a deferential tone.