Speak concisely, say much in few words: Contemporary English Version is helpful with “and say as much as you can in as few words as possible.”

Be as one who knows and yet holds his tongue may be rendered “This will show that you are knowledgeable and also that you have self-control.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on Sirach. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here.