After surgical intervention of tongue cancer, it has been hard to avoid articulation disabilities of varying degrees. It has been our invariable opinion that if a way of predicting the degree of disability for each operation could be devised, it would be of invaluable help in the choice of operations and postoperative articular rehabilitation. We have studied the degree of articulation disabilities that developed postoperatively in fifteen patients with monosyllables word intelligibilty test and speech intelligibility test from February 1988 to May 1990. To test monosyllable intelligibility, the patient was asked to speak out loud 100 monosyllables used in everyday conversation and analysized the degree of understanding by normal persons. To test speech intelligibility, We had both acquaintance and nonacquaintance of the patient as listeners and We asked the patient to perform a normal speech. Responses by the listner were graded into 5 levels according to the degree of understanding. The postoperative articulation disabilities seemed to be closely related to the degree of excision and disabilities were greatest when the excision involved the oropharynx, floor of oral cavity and tongue base. In performing partial glossectomy, results obtained by excision performed by simple suture were found to be worse than the excision performed by the laser. Also the partial excision involving the tongue base had the worse disabilities than the excision involving only the mobile portion of the tongue. Even if the mobile portion was excised, when the operation included the oropharynx, tongue base and the mandible the disablities were more severe than when subtotal glossectomy using a Pectoralis muscle flap was done. The results of subtotal glossectomy with reconstruction of the mouth floor was better than we had expected.