Catherine, your post really choked me up. Definately sounds like Apraxia. Have you ever looked into any supplements like EFA's? They help a lot of kids. I like Nordic Naturals ProEFA or Calson. They're nice and pure.
Was she vaccinated? My thoughts are that considering 1 in 5 kids is now on the Autism spectrum that they must be related. Apraxia and Autism that is. Does she have any food allergies? Problems with yeast? Have you ran any tests through the pediatrition? Many Apraxic kids are low in Iron. There are little things that you can do to help her. We follow the Feingold Diet. Organic, no wierd chemicals or dyes. Some people see improvement with the GFCF (gluten free casein free) diet. Also, a quality B Complex vitamin has helped my son.
I'm sure you've read books on Apraxia but a good one for treating Autism (even though she's not Autistic)is Healing The New Childhood Epidemics (The 4 A's Autism, ADHD, Asthma and Allergies) by Kenneth Bock.
If you use Facebook I'll friend you. We have a large group of parents with these kind of problems.