intone (v.1)

late 14c., entunen "sing, chant, recite, vocalize," from Old French entoner "to sing, chant" (13c.), from Medieval Latin intonare "sing according to tone," from Latin in- "in" (from PIE root *en "in") + tonus "tone," from Greek tonos, from PIE root *ten- "to stretch." Related: Intoned; intoning.

intone (v.2)

obsolete 17c.-18c. verb, from French entoner "thunder, roar, resound, reverberate," from Latin intonare "to thunder, resound," figuratively "to cry out vehemently," from tonare "to thunder" (see thunder (n.)). Related: Intoned; intoning.