I have a big problem. I sometimes have a hard time following when two or more native speakers are talking together in French or Spanish. I can have a one on one conversation with native speakers of these languages, but when they get in a group and start talking, it’s often hard to follow their conversation. I guess this is a common problem for any language learner, who does not spend their entire day immersed in the target language environment.
For native speakers, there are different levels of speaking a language. By this I mean in what context you are talking the language and to whom. For example if you are giving a lecture in front of a class, you are going to be speaking differently, using different words and speaking more clearly, than if you are having a casual conversation with friends. In order to truly master a language, you need to be comfortable at all these levels.