Anyway, I'm teaching myself and my primary text is McGregor's Outline of Hindi grammar. It's rather heavy on the grammar, but that's how I like it. For balance, though, I'm supplementing it with Matthews' and Dalvi's Teach yourself Urdu. Now, I've always been told that, on the colloquial level, Urdu and Hindi are indistinguishable. But I'm finding significant divergences between the two books. What I don't know, however, is how much is due to actual linguistic variation and how much is just differences in the authors' approaches.
The first thing I noticed was a difference in polite expressions. McGregor teaches only आप कैसे हैं? aap kaise haiM? for "How are you?" whereas TYU has क्या हाल है? kyaa haal hai? Is the latter used in Hindi, too, or only Urdu? What about the response, आप की दुआ है aap kee duaa hai?
Another difference is in the words for "here" and "there". In the sense of "to here", TYU uses the special word इधर idhar (e.g. आओ इधर! aao idhar!). But this isn't found at all in McGregor, who uses यहां yahaaM for both direction and location. How common is इधर idhar in Hindi? Can you get by without it? And what about related words (e.g. उधर udhar, किधर kidhar)?