Exercising the tongue.
Pearson
A
A
D019348:Empiricism; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D008445:Maxillofacial Development; D020247:Myofunctional Therapy; D017289:Orthodontic Appliances, Functional; D014059:Tongue / Q000502:physiology