“The tongue of the righteous is choice silver”: “The tongue” is used here, like “the lips” in verses 18-19, to refer to words or speech. “The tongue of the righteous” means the speech or words of a good person. For “choice silver” see 8.10 and 19. We may translate this line, for example, “Words spoken by a good person are as valuable as the purest silver.”

“The mind of the wicked is of little worth”: “Mind” is literally “heart.” The contrasting parallelism is between “The tongue of the righteous” and “the mind of the wicked” and between “choice silver” and the more general “little worth”. This line may be rendered, for example, “The thoughts of the wicked have little worth” or “What the wicked think is of little value.”

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 .