If you have a slurred speech, you should first rule out a short tongue ligament. If the tongue ligament is short, the tongue is not pointed, so some sounds cannot be pronounced or spit out clearly because it is not pointed. Secondly, a deep groove on the top of the tongue after sticking out indicates a short tongue ligament, which can be done by a small surgery in the dentistry department. If there is no problem with the tongue ligament, you should have your hearing checked to see if you have neurological deafness or secretory otitis media, both of which can cause inaudibility and therefore unclear biting. Besides, if there is no problem with both, it is the way of pronunciation, which needs to be corrected by professionals for pronunciation.