As the stamp of great minds is to suggest much in a few words, so, contrariwise, little minds have the gift of talking a great deal and saying nothing.
François VI, duc de La Rochefoucauld (1613-1680) French epigrammatist, memoirist, noble Réflexions ou sentences et maximes morales [Maxims], #142 (1665) [tr. Tancock (1959)]
(Source)
We seldom regret talking too little, but very often talking too much. This is a well-known maxim which everybody knows and nobody practices.
[L’on se repent rarement de parler peu, très souvent de trop parler: maxime usée et triviale que tout le monde sait, et que tout le monde ne pratique pas.]
Jean de La Bruyère (1645-1696) French essayist, moralist The Characters [Les Caractères], ch. 11 “Of Mankind [De l’Homme],” § 149 (11.149) (1688) [tr. Van Laun (1885)]
(Source)
We seldom repent talking too little, but very often talking too much, a common and trivial maxim which every body knows, and no body practices.
[Bullord ed. (1696) and Curll ed. (1713)]
We seldom repent talking too little, but very often talking too much; a common obsolete Maxim, which every body knows, and no body practices.
[Browne ed. (1752)]
We seldom repent of speaking little, and very often of speaking too much; a well-worn and familiar maxim, that everyone knows but that not everyone practices.
[tr. Stewart (1970)]
To listen closely and reply well is the highest perfection we are able to attain in the art of conversation.
François VI, duc de La Rochefoucauld (1613-1680) French epigrammatist, memoirist, noble Réflexions ou sentences et maximes morales [Maxims] (1665-1678)
Speak properly, and in as few words as you can, but always plainly; for the End of Speech is not Ostentation, but to be understood.
William Penn (1644-1718) English writer, philosopher, politician, statesman Some Fruits of Solitude, Part 2, “Of Conduct and Speech,” #122 (1682)
(Source)