Tongue (lower surface): fleshy, mobile organ situated in the mouth of humans, used to taste, swallow and speak.
Superior dental arch: set of teeth of the upper jaw.
Sublingual fringe: fringe beneath the tongue.
Lingual vein: vein of the tongue.
Sublingual protuberance: a projection under the teeth.
Openings of the ducts of the submandibular and sublingual salivary glands: papillae situated beneath the tongue.
Lower lip: lower external part of the mouth, covering the tongue.
Frenulum of the tongue: membrane that prevents a person from swallowing his or her tongue.
Upper lip: upper external part of the mouth, coverint the teeth.

Photo :

EN : Tongue lower surface
FR : Langue face inférieure
ES : Lengua cara inferior

          lower surface

Since the tongue contains no bony supports for the muscles, the tongue is an example of a muscular hydrostat, similar in concept to an octopus arm. Instead of bony attachments, the extrinsic muscles of the tongue anchor the tongue firmly to surrounding bones and prevent the mythical possibility of 'swallowing' the tongue.