Albert Barnes Commentary Proverbs 15:4

"A gentle tongue is a tree of life; But perverseness therein is a breaking of the spirit." — Proverbs 15:4 (ASV)

A wholesome tongue - literally, as in the margin, the same word as “sound” in (Proverbs 14:30) (see the note). A more literal rendering would be soundness of speech.

Tree of life - Compare (Proverbs 3:18) note.

Breach in the spirit - With the sense of vexation .