Good point - I'd forgotten about normal hearing people who are illiterate.
In the case of illiterate deaf people with good speech skills I'm not sure though that it's correlated specifically to the fact that they were raised orally (I'm assuming they were). I'd say it was more about the quality of their education program whether oral or not. In a well managed program, someone who is able to acquire good speech skills should be able to develop good literacy as well, since its the same language.
