Which preposition to use with singsong

of Occurrences 1%

Except for the breach by which they had entered, the blotched and spotted compound walls stood ruinous yet high, shutting out all but a rising slant of sunlight, and from some outpost line of shops, near by, the rattle of an abacus and the broken singsong of argument, now harsh, now drowsy.

Which preposition to use with  singsong