That is a rare disease typically any muscular disorder is going to cause issues with speech and swallowing because the muscles you use for swallowing and talking. It sounds like you aren't able to manage you saliva by swallowing it naturally which is a common issue in swallowing disorders. Keep up the work the speech therapist it takes a lot of repetition to improve your swallowing and speech. They are skills we take for granted until we lose them and actually have to think so hard to move your mouth and throat to swallow.