We all go through good periods and bad. These can range from weeks to months or longer. There's just a lot of ups and downs. I would recommend going to see a speech pathologist if you haven't. A lot of family think what's best is to not draw attention to the "problem" but no one is fooled. Kids arent dumb. I dont know how old your son is but it certainly will not make anything worse by taking him, giving him an opportunity to talk about it and you could get some good treatment.