Nouns

(n)singsonga regular and monotonous rising and falling intonation
(n)singalong, singsonginformal group singing of popular songs

Verbs

(v)singsongspeak, chant, or declaim in a singsong
(v)singsongmove as if accompanied by a singsong“The porters singsonged the travellers' luggage up the mountain”

Adjectives

(s)chantlike, intoned, singsonguttered in a monotonous cadence or rhythm as in chanting“their chantlike intoned prayers”, “a singsong manner of speaking”