I can't say that I have the same compulsion that you do about speech, but one way or another, OCD has a strange way of making itself known. Actually now that I think about it, I used to repeat certain words in sentences. Like if I stopped talking, I had to repeat the same thing over again even if I said it fine the first time. Eventually it just sort of went away.
As for your mother having OCD, the debate is split down the middle. Is it genetic, or is it because of the environmnet? My parents don't have OCD, and no one in my family does except for me. The debate will rage on, but as for me I think it has alot to do with the enviornment you're rasied in, and how you dealt with things as a child.
As children our minds are not yet old enough to understand how to deal with things we see at home, or in life. Depending on our sensitivity, we may repress being yelled at, or seeing our parents divorce at an early age, or not know how to deal with some tragic accident. As we get older, these things that have sat in our sub-concious for so long have a funny way of coming out, which is in the form of OCD.
My recommendation would be to see a CBT (Cognitive Behavrioal Therapist) and get into therapy, as the therapist will be able to help you start to overcome your OCD.