I think you could say the same of any film in the original language to learners of that language. I have been living in Italy for 8 years and although my Italian is quite good, I have problems understanding films. Having said that, it depends on the type of film. Fast action films set in modern times are much harder to understand than romantic films or historical dramas because the language in the former is more colloquial and the speech is usually faster, whereas in the latter (historical dramas) the language is closer to the English you study because the vocabulary has to be reasonably authentic and most slang and colloquialisms didn't exist 100 or more years ago. So, choose films that are set in the past such as film versions of classic literature or films set in historical times. Watching English films with English subtitles will also increase your understanding by a lot.

YOU CAN WATCH FREE MOVIES AND LISTEN TO SPOKEN ENGLISH WHILST READING THE SUBTITLES IN YOUR OWN LANGUAGE at : www.itv.com and www.free-tv-video-online.info/ Listen to speeches on line about a variety of current issues at: www.ted.com and listen to how words are pronounced in Formal English Here's another site for you: http://www.bbc.co.uk/iplayer/ http://en.yappr.com/welcome/Welcome.action http://www.yolango.com/ http://www.bbc.co.uk/radio4/

Because sometimes they don't use traditional English (i.e Slang), and they talk really fast. But I think you need to find films with "subtitles" on them.