I'm not deaf myself, but where I live the deaf just ride bikes, because everybody rides bikes. But I guess it takes more courage in North-America. Quite recently there's a new sign made deaf people can wear on their bike or backpack to alert other cyclists and motorists that they can't hear you coming. There's also a university involved in the development of a machine that helps deaf people to detect traffic behind them, but I wouldn't count on a finished product very soon.

Also there's some annual event here which attract young deaf people from over the world, I don't know what it is, I just see them in the city center talking with their hands, also while riding bikes. Of cours they have their language troubles to, but they seem to work them out much faster. But it's not uncommon here to bike with headphones or earplugs and without hands, so in terms of cycling behaviour they're not that special.

Personally I like the 360 degree range of my hearing in cycling, but still don't like low bars because I see a lot less of the traffic that way. I don't know what kind of bike you ride, but you might consider high handlebars and a fully upright position, because it widens your view considerably.