I believe that part of the reason they ask for details etc is just to keep you on the phone and talking. That might sound odd but in most emergencies this is actually desirable because it keeps you calm and focussed. And in the case of you phoning in an injury to yourself (for example) it also helps keep you concious and stops you going into shock. Of course, just taking your address isn't going to keep you engaged for long enough for an ambulance to arrive but it does get the dialogue rolling. I don't know if that's actually true but I've heard it from more than one source.

And of course they check your address and details if you're able to give it. Why would they pass up an opportunity to trivially build redundancy into the system? That doesn't mean they'll fold their arms and ignore your call if you're unable to speak, though.