Charles H. Spurgeon on Psalms 140:11

An evil speaker. By "a man of the tongue", as the original has it, the Hebrews express a detractor or sycophant; one who gives his tongue the liberty to vent what mischief lie pleases. The Chaldee here expresses it by a delator or vile informer with a threefold or three forked tongue;because such a man wounds three at once; the receiver, the sufferer, and himself. —Thomas Fenton.