Talk sense to a fool
and he calls you foolish.

[δόξει τις ἀμαθεῖ σοφὰ λέγων οὐκ εὖ φρονεῖν.]

Euripides (485?-406? BC) Greek tragic dramatist

Bacchæ [Βάκχαι], l. 480 [Dionysus/Διόνυσος] (405 BC) [tr. Arrowsmith (1960)]
    (Source)

Replying to Pentheus' charge that he's being foolishly evasive.

(Source (Greek)). Alternate translations:

He must seem devoid
Of reason, who mysterious truths unfolds
To those who lack discretion.
tr. Wodhull (1809)]

One will seem to be foolish if he speaks wisely to an ignorant man.
[tr. Buckley (1850)]

Who wiseliest speaks, to the fool speaks foolishness.
[tr. Milman (1865)]

Boors think a wise man’s words devoid of sense.
[tr. Rogers (1872), l. 457]

He were a fool, methinks, who would utter wisdom to a fool.
[tr. Coleridge (1891)]

Wise answers seem but folly to a fool.
[tr. Way (1898)]

Wise words being brought
To blinded eyes will seem as things of nought.
[tr. Murray (1902)]

He who talks wisdom to an ignorant man will seem out of his senses.
[tr. Kirk (1970)]

A wise speech sleeps in a foolish ear.
[tr. Vellacott (1973)]

Talk truth to a deaf man and he
Begs your pardon.
[tr. Soyinka (1973)]

Wise speech seems thoughtless to the ignorant.
[tr. Neuburg (1988)]

What makes no sense is talking sense to a fool.
[tr. Cacoyannis (1982)]

To the ignorant, wisdom will seem folly.
[tr. Blessington (1993)]

To the ignorant man, any speaker of wisdom will seem foolish.
[tr. Esposito (1998)]

Speak wisdom to a fool and he'll think you have no sense at all.
[tr. Woodruff (1999)]

Wise things to the ignorant will sound like nonsense.
[tr. Gibbons/Segal (2000)]

Speak wisdom to a fool and he will think you foolish.
[tr. Kovacs (2002)]

Wise words spoken in the ear of a fool turn into nothingness.
[tr. Rao/Wolf (2004)]

It is not wise for someone to say anything wise to the ignorant.
[tr. Theodoridis (2005)]

Wise words will appear foolishness -- to an idiot.
[tr. Valerie (2005)]

Yes, but, then,
a man can seem really ignorant
when speaking to a fool.
[tr. Johnston (2008)]

Sense is nonsense to a fool.
[tr. Robertson (2014)]

Wisdom always sounds silly to the unwise.
[tr. Pauly (2019)]

Only a fool takes a warning for an insult.
[tr. Behr/Foster (2019)]

One will seem to be foolish if he speaks wise things [sopha] to a senseless man.
[tr. Buckley/Sens/Nagy (2020)]