Pam Marshalla is a leader in the nation-wide oral-motor movement. She has presented hundred of workshops on oral-motor, apraxia and articulation therapy to tens of thousands of speech and language pathologists who have attended her state, regional and national conferences.
Looking for the right book by Pam Marshalla?
If you are looking for information specifically about ways to facilitate jaw, lip, and tongue movements, read Oral Motor Techniques in Articulation and Phonological Therapy. This book also discusses methods to normalize oral tactile sensitivity. In this book you will discover that oral motor techniques are NOT simply "wagging the tongue."
If you are looking for specific training material for teaching /r/ go to Successful R Therapy. If you are looking for material on the sibilants, go to Frontal Lisp, Lateral Lisp. Both of these books were written for speech-language pathologists and are not appropriate for parents. They present an integration of traditional articulation therapy methods along with tactile and proprioceptive stimulation techniques for oral movement specific to the sibilants and /r/.