Meaning
The various uses of "tongue" in English are all possible also for lashon and glossa, whether as the physical organ (Exod 11:7, Mark 7:33, etc.) or as meaning "language" (Gen 10:5, Acts 2:4, etc.) or as describing anything shaped like a tongue (Isa 11:15, Acts 2:3, etc.). In addition, both words, especially lashon appear in a wider range of meanings than can be taken by "tongue" in modern English. So the tongue appears as the specific organ of speech, where we should prefer "mouth" or "lips" (Exod 4:10, Ps 71:24, Ps 78:36, Prov 16:1, Phil 2:11, etc.), and hence, "tongue" is used figuratively for the words uttered (Job 6:30, Ps 139:4, 1John 3:18, etc.). So the tongue can be said to have moral qualities (Ps 109:2, Prov 15:4, etc.) or to be "glad" (Ac 2:26); to "love with the tongue" (1Joh 3:18) is to love in word only, and to be "double-tongued" (Wisdom of Sirach 5:9, 28:13, 1Ti 3:8 is to be a liar. A further expansion of this figurative use has produced expressions that sound slightly bizarre in English, although their meaning is clear enough: e.g., "Who have whet their tongue like a sword" (Ps 64:3); "His tongue is as a devouring fire" (Isa 30:27); "My tongue is the pen of a ready writer" (Ps 45:1), and, especially, "Their tongue walketh through the earth" (Ps 73:9).
In Job 20:12, "Though wickedness be sweet in his mouth, though he hide it under his tongue," the figure is that of an uncultured man rolling a choice morsel around in his mouth so as to extract the utmost flavor. In Ps 10:7, Ps 66:17 (Revised Version margin), however "under the tongue" means "in readiness to utter," while in So 4:11, "Honey and milk are under thy tongue," the pleasure of a caress is described. To "divide their tongue" (Ps 55:9) is to visit on offenders the punishment of Babel.
Burton Scott Easton