This is a case report of a patient with soft palate muscle weakness that caused difficulties with phonation. A provisional palatal lift prosthesis (PLP) was developed, and the patient underwent simultaneous speech therapy. The elevation level of the palatal lift was subjectively assessed along with nasalance analysis and the Urimal Test of Articulation and Phonation results. The final PLP was applied to improve comfort and efficiency, and the patient continually underwent regular speech therapy. The patient showed satisfactory improvement in speech and pronunciation. PLP development combined with speech therapy can improve the accuracy of pronunciation in patients with palatal incompetence, thereby improving quality of life.