Proverbs 25:15 New English Translation

¹⁵Through patience^[a] a ruler can be persuaded,^[b]
and a soft tongue^[c] can break a bone.^[d]

Proverbs 25:15 tn Heb “long of anger” or “forbearance” (so NASB).
Proverbs 25:15 tn The two imperfect verbs in this line may be nuanced as potential imperfects because what is described could happen, but does not do so as a rule.
Proverbs 25:15 tn The “tongue” is a metonymy of cause; and so the expression here refers to soft or gentle speech. This fits well with the parallel idea of patience (“long of anger”)—through a calm patient persuasion much can be accomplished. Some English versions relate this figure directly to the persuasion of a ruler in the previous line (cf. TEV “can even convince rulers”).
Proverbs 25:15 sn The idea of breaking a bone uses the hardest and most firm part of the body in contrast to the “softness of the tongue.” Both are figurative, forming a comparison. A gentle speech can break down any stiff opposition.

New English Translation (NET)