Ankyloglossia
A doctor can diagnose this condition during a physical exam. The exam will show that the tongue tissue is attached too far forward.
Behrman RE. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: WB Saunders; 2004.
Cummings CW, Flint PW, Haughey BH, et al. Otolaryngology: Head & Neck Surgery. 4th ed. St Louis, Mo; Mosby; 2005.