Drawing on my fine command of language, I said nothing. – Attributed to Robert Benchley by Evan Esar in 1949, however a similar saying alr

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

And there is monologue disguised as dialogue, in which two or more men, meeting in space, speak each with himself in strangely tortuous and circuitous ways and yet imagine they have escaped the torment of being thrown back on their own resources. – Martin Buber (1878—1965), translated from German