:: Shahid, you keep saying that Urdu is used only "rarely". I get a sense that what Urdu means to you is a word that feels odd or foreign. But most of the everyday words (like "jawan" and "aap" and "shadi") are the SAME in both dialects/languages. If an Urdu-speaker can understand 100% of the dialogues in most movies, doesn't that mean that the dialogues are 100% colloquial Urdu? Also 100% colloquial Hindi? 

 Difference in script doesn't mean difference in language. When the Young Turks took over Turkey, they decided that Turkish was henceforth to be written in Roman rather than Arabic script. Does that mean that Turkish before the government-imposed change was a different language? I don't think so.