I tried speech therapy on my own but it really doesn't work unless you know where the issues are.
After my child was tested I knew what to train, there are a lot of things you and I don't hear but the therapist will catch.
I belive you can do the work at home and don't need a therapist except for consultation every once in a while. I did take my child to therapy for 2 years once a week and had great results, but it was on a sliding scale and I could afford it, it was sure easier than doing it myself.
here is a site that has some practice work you can see how it is laid out:
http://www.deafhomeschool.com/essential ... tions.html
that sight also some great links with, ideas for therapy with parents etc.. but the key is to know what is wrong before you start. I would use a non profit or university, testing rather than a "professional" To get a accurate test.
My dd had problems with s's, the concept of more, and "w" question words also stumped her. Even to this day she can't answer "why" questions unless I make them "what" questions.. And I never would have caught that! I would have though she was just being obtuse.