Saying meaning "Don't speak unless you can improve silence"

There's this fairly famous saying:

"Better to remain silent and be thought a fool than to speak and remove all doubt."

A quick internet search indicates that this saying has been attributed to Mark Twain, Abraham Lincoln, and Confucius, among others.

There's a proverb:

"Speech is silver, silence is golden".

Our mamas always told us:

If you don't have anything nice to say, don't say, anything at all!

Let not thy tongue run away with your brains

I'm not sure whether it is of English origin, but it has been around for a while, since it can be found in:

Gnomologia: Adagies and Proverbs; Wise Sentences and Witty Sayings, Ancient and Modern, Foreign and British collected by Thomas Fuller; B. Barker ... and A. Bettesworth and C. Hitch, 1732

A modern version can also be found (on-line at least):

Let not your tongue run away with your brains.

Source: http://www.bartleby.com/89/1785.html

Speech is of time, silence is of eternity.

— Thomas Carlyle, Sartor Resartus

It is the wise head that makes the still tongue.

— W. J. Lucas

it is an old Arabic proverb, in spanish litrature they attributed this saying to the arab way way back in the moorse time. another one from Arabia. if talking is made of silver, silence is from gold.

“If what one has to say is not better than silence, then one should keep silent.”

― Confucius

There is such a proverb but I am not sure it is very common:

Speaking silence is better than senseless speech.

I found a funny saying which I can't help mentioning:

“Never miss a good chance to shut up.” (Will Rogers)

I also like George Elliot's way of saying this:

“Blessed is the man who, having nothing to say, abstains from giving us wordy evidence of the fact.”