Is there a significant difference between the three expressions, or can they be used interchangeably?
I'm trying to say that a colleague of mine succeeded to another after the latter had quit his job.
Did he "take the role" of his colleague or did he "take over the role" of his colleague? Also "take on the role" sounds like a viable option to me, because I'm trying more to convey the sense of him accepting a new challenge rather than simply taking possession of something that wasn't his.
It's so hard for me as a non-native speaker to say exactly what I mean, I hope you can help me.
Best Answer
There is no significant definitional difference between the three expressions, but they differ in connotation, so they cannot exactly be used interchangeably either.
"To take a role" is a neutral expression, which can be used in a variety of ways but usually serves as a denotation that implies nothing else. It doesn't seem like what you're looking for.
"To take over a role" is, as you said, to take a role that was previously occupied by somebody else, which seems to be what you're looking for, as your colleague "replaced" another worker, so he "took over" that worker's role.
"To take on a role" is, again as you said, to accept the role as a challenge. However, you seem to be emphasizing the replacement aspect more than the challenge aspect, at least from what I can tell by your description.
I'd personally recommend "take over the role".