I remember seeing a doco or movie or something about a figure skater who could feel the music so she knew when to make her moves.
Its an interesting point, like I wonder what language a dog thinks in? They dont have a spoken language do they, but my dog definitely thinks.
Another interesting and totally irrelevant point. I'm colour blind, just standard red/green, and I've been asked before why I don't go at red lights and stop at green ones. Colour blindness means you have trouble distinguishing shades, its not what people imagine it to be, but it poses an interesting point.
If I look at a red light, I can tell you its a red light. I cant guarantee its the same colour that you are seeing, for all I know I am actually seeing a green light. But all my life, people have been pointing at that colour and telling me its red.. so regardless of what colour I am actually seeing, I've always called it red, and its just a normal red traffic light..
Some shades of red or green can blend together and look very similar to me, but not the ones at traffic lights. The worst thing is trying to find one of those flouro yellow balls on a green golf course.. they are invisible to me from any more than about 6 feet away.
The point of that little story? You know what you learn. If you are deaf, you learn to cope in some other way. If you don't have a spoken language to verbalise something in your head, you will still be able to do it. You just wont know you are doing it or how.
If a deaf person reads a book, they can understand what its saying. They may not speak it to themselves in the same way we do, but they must have some internal language or something they can fall back on.. they would understand, read and write english, but it just wouldn't sound like english if they were to try to say it.
Same as my red light, it doesn't matter what colour it really is so long as the end result is that I know its time to stop..