“She opens her mouth with wisdom”: This is not very natural in English. The expression “She opens her mouth . . .” is an idiomatic way of saying “She speaks. . .” (New International Version, Good News Translation); see verse 8. Revised English Bible expresses the whole line as “When she opens her mouth, it is to speak wisely”; but this is more than the text requires, and New International Version “She speaks with wisdom” and Contemporary English Version “Her words are sensible” are good and clear models for translators.

“And the teaching of kindness is on her tongue”: For “teaching” see 1.8. In the expression “the teaching of kindness” the Hebrew term rendered “kindness” is chesed. This term may mean “love” or “kindness,” but it may also have the sense of “faithfulness” or “loyalty.” So on the one hand “the teaching of kindness” may mean something like “kindly instruction” (Scott, New Jerusalem Bible) or “her advice is thoughtful” (Contemporary English Version); on the other hand it may mean “faithful instruction” (New International Version) or “her teaching is sound” (Revised English Bible). “Is on her tongue” is an expression similar to “opens her mouth” in the previous line. It may be rendered in English simply as “her [instruction or advice].” Good News Translation appears to render this whole line by the single word “gentle,” but this really misses a number of elements of the meaning, and translators are advised not to compress the verse as Good News Translation has done.

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Proverbs. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .