Non-speech oral motor exercises: do they help develop speech?

Claims about the efficacy of oral motor therapy in supporting the development of speech in children with Down syndrome have been somewhat controversial, with little research evidence to support it.  

Jennifer Bekins recently posted a link on her blog, Let's talk - Down Syndrome, to a summary of questions, rationales and evidence, Parent‐Friendly Information about Nonspeech Oral Motor Exercises, presented at the American Speech and Hearing Association conference in 2011.

The information sheet makes important distinctions between speech and non-speech motor activity, and explains that muscle tone and muscle strength are different phenomena.