This study examined the effects of orofacial myofunctional therapy (OMT) on speech intelligibility in adults with persistent articulation impairments. Six adults in the age range of 18-23 years were selected to receive OMT for a period of six weeks. Speech intelligibility increased significantly in all clients except the one diagnosed with developmental apraxia of speech. Orofacial myofunctional therapists, speech-language pathologists, and other professionals need to rule out underlying orofacial myofunctional variables when targeting speech sounds for intervention.

Ray, J. (2003). Effects of orofacial myofunctional therapy on speech intelligibility in individuals with persistent articulatory impairments. International Journal of Orofacial Myology. 29, 5-11.