Adam Clarke on Psalms 12:2

They speak vanity every one with his neighbor - They are false and hollow; they say one thing while they mean another; there is no trusting to what they say.

Flattering lips, and with a double heart do they speak - בלב ולב beleb valeb, "With a heart and a heart." They seem to have two hearts; one to speak fair words, and the other to invent mischief. The old MS. both translates and paraphrases curiously.

Trans. Dayn spak ilkan til his neghbur: swykil lippis in hert, and thurgh hert thai spak.

Par - Sothfastnes es lessed, and falsed waxes: and al sa vayn spak ilkone to bygyle his neghbur: and many spendes thair tyme in vayne speche withoutyn profyte and gastely frute. And that er swyku lippis; that er jangelers berkand ogaynes sothfastnes. And swykel, for thai speke in hert and thurgh hert; that es in dubil hert, qwen a fals man thynkes ane, and sais another, to desaif hym that he spekes with.

This homely comment cannot be mended.