An example embodiment of the present disclosure provides a sublingual dental appliance for treatment of Orofacial Myofunctional Disorders (OMDs). The sublingual dental appliance may be a semi-permanent physical training device that guides the tongue into the appropriate position in the mouth, thereby training the muscles to address a disorder. The sublingual device may feature a pair of support structures that guide the tongue into the appropriate relationship with the palate, with the tongue directed in a superior angle to the superior portion of the mouth, against the hard palate, during both use and rest. Although the appliance may be semi-permanently affixed to the individual, the support structures of the appliance are directly affixed to flexible, adjustable elements that may be adjusted during use to reconfigure the angle or position of the support structures as needed during treatment.