Well, that's why I say one should know the grammar more or less.

By the way, the language in movies is not always being spoken that rapidly. In every movie one can hear several phrases (or parts of phrases which is not bad also) quite distinctly. For example, I hardly speak and understand French (I almost don't), but when I watch some French film, or, say, even Sarkozy's speech, I'm able to make out some separate words or phrases sometimes, and I think that when I understand only few words, it helps anyway because I hear how a native in his live speech pronounce them and I can make out on my own.

Well, I say that it's me who prefers this method, and I don't make anyone to do the same.

P.S.
language is being spoken so rapidly they can't pick up on the terms being used
One can, if he has the text.