What's the "een" in Halloween?
1640s, from Medieval Latin lingualis "of the tongue," from Latin lingua "tongue," also "speech, language," from Old Latin dingua, from PIE *dnghu- "tongue" (cf. Old English tunge, Gothic tuggo "tongue;" see tongue). Altered in Latin probably in part by association with lingere "to lick."
lingual lin·gual (lĭng'gwəl)
Of or relating to the tongue or any tonguelike part; glossal.
Next to or toward the tongue.