TONGUE. A flexible mass of tissue attached to the lower back of the mouth of most vertebrate animals; an aid to chewing and swallowing, the organ of taste, and an important component in the articulation of SPEECH. Words for ‘tongue’ in many languages stand for speech itself. English has a number of words and phrases of different origin which do this: language, through French langue, from Latin lingua, tongue; linguistics, directly from Latin; polyglot and isogloss, from the Greek glṓssa, tongue; the phrases mother tongue, foreign tongue, and the Biblical gift of tongues; such idioms as Has the cat got your tongue? (said to someone who will not speak), to bite one's tongue (to remain silent despite provocation), it's on the tip of my tongue (I know it but I can't quite recall it), Hold your tongue (Be quiet).

In terms of anatomy and PHONETICS, the tongue has five parts: the tip (of the tongue), the blade (of the tongue), the front (of the tongue), the back (of the tongue), and the root, which lies not in the mouth but in the pharynx. Sounds made at the tip (the ‘apex’ of the tongue) are apical. The blade is immediately behind the tip, lies opposite the alveolar ridge of the upper mouth when the tongue is in a state of rest, and sounds made with the blade (Latin lamina) are laminal. The area behind the blade is the front, which lies opposite the hard palate when the tongue is in a state of rest, and sounds made with the front are palatal. The back of the tongue lies opposite the soft palate or velum when the tongue is in a state of rest, and sounds made with the back include velar consonants and back vowels.