Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
singsong [ˈsɪŋsɔŋ] adj (tone) моното́нно иду́щий то вверх, то вниз
n
to have a singsongпопе́ть*(perf) хо́ром
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.