I learnt Spanish from watching TV in Spain for 3 years. It was never subtitled, always dubbed. Had it been subtitled though, I would have read the subtitles instead of concentrating on the Spanish. When forced to listen and understand (or not), I learnt very quickly. Essentially, a lack of subtitles forces the viewer to focus on the language (the oral dialogue) rather than on the easier written transcription of subtitles. Watching films like this is a great way to learn a language, but you must be prepared to put in a lot of work. It's a long, frustrating road. Lastly, always have your dictionary at hand to look up new words.