To speak and to speak well are two things. A fool may talk, but a wise man speaks. ~Ben Jonson
Most conversations are simply monologues delivered in the presence of a witness. ~Margaret Millar
Of those who say nothing, few are silent. ~Thomas Neiel
The older I grow the more I listen to people who don't talk much. ~Germain G. Glien
I am annoyed by individuals who are embarrassed by pauses in a conversation. To me, every conversational pause refreshes. ~George Sanders
Don't speak unless you can improve on the silence. ~Spanish Proverb
Isn't it surprising how many things, if not said immediately, seem not worth saying ten minutes from now? ~Arnot L. Sheppard, Jr.
Blessed is the man who, having nothing to say, abstains from giving evidence of the fact. ~George Eliot, Impressions of Theophrastus Such, 1879
The difference between a smart man and a wise man is that a smart man knows what to say, a wise man knows whether or not to say it. ~Frank M. Garafola
In the course of my life, I have often had to eat my words, and I must confess that I have always found it a wholesome diet. ~Winston Churchill
And, the quote for which I initially searched:
Never argue with a fool, onlookers may not be able to tell the difference. ~ attributed to Mark Twain
I encourage those who have ideas and are able to act to do so because those who have nothing of value to add will likely continue to talk. I learned in school that "empty barrels make the most noise" (these days they do so eloquently) and I suspect that much hasn't changed.
Stop by my Urban Yard Jamaica shop some time and check out what else I've been up to. You just might see something there that you like. If you don't see anything then make a suggestion.