Meaning

verb speak carefully, as with rising and falling pitch or in a particular tone

verb recite with musical intonation; recite as a chant or a psalm

originFirst attested in 1795; borrowed from Medieval Latin intonātus, perfect passive participle of intonō (“to vocalize, chant”) (see -ate (verb-forming suffix)), from in- (inchoative prefix) + tonus (“pitch, tone”) + -ō (verb-forming suffix); doublet of intone. Cognate with French entonner, Italian intonare.

Etymology from Wiktionary, CC BY-SA 3.0