sing vs intone

sing and intone both are verbs.

Word	Noun	Adjective	Verb	Adverb
sing	No	No	Yes	No
intone	No	No	Yes	No

As verbs, intone is a hyponym of sing; that is, intone is a word with a more specific, narrower meaning than sing:

sing (verb)	intone (verb)
make a whining, ringing, or whistling sound	recite with musical intonation; recite as a chant or a psalm
divulge confidential information or secrets	speak carefully, as with rising and falling pitch or in a particular tone
to make melodious sounds	utter monotonously and repetitively and rhythmically
produce tones with the voice
deliver by singing