Immediately prescribe some character and some form to yourself, which you shall observe both when you are alone and when you meet with men. And let silence be the general rule, or let only what is necessary be said, and in few words. And rarely and when the occasion calls we shall say something; but about none of the common subjects, not about gladiators, nor horse races, nor about athletes, nor about eating or drinking, which are the usual subjects; and especially not about men, as blaming them or praising them, or comparing them. […]
The prescription is severe by modern standards. The reason is that conversation defaults to status-jockeying — who is up, who is down, who said what. The Stoic suspects that most speech is a low-grade form of competition. The recommendation is not antisocial; it is anti-noise. Speak when there is reason. Otherwise listen, or stay quiet.
Epictetus, Enchiridion 33 · trans. George Long (1877)
Context
Toward the end of Epictetus' Enchiridion. The chapter contains a long set of behavioural prescriptions — how to speak, eat, dress, behave at public spectacles — a catalogue of kathēkonta, appropriate actions. The framing principle is what matters here — choose your standard, hold it, expect to look strange.