Albert Barnes Commentary Psalms 50:19

"Thou givest thy mouth to evil, And thy tongue frameth deceit." — Psalms 50:19 (ASV)

You give your mouth to evil - Margin, as in Hebrew, “you send.” That is, they gave it up to evil; they employed it in evil: in falsehood, malice, deceit, slander, deception, detraction.

And your tongue frames deceit - The word rendered “frameth” means properly to bind, to fasten; and then, to contrive, to frame. The meaning is, that it was employed in the work of deceit; that is, it was employed in devising and executing purposes of fraud and falsehood.