Mother-in-law rhymes with:
mothers-in-law, greenlaw, kinlaw, mothers-in-law, bylaw, dewclaw, fallaw, greenlaw, holtsclaw, kinlaw, laidlaw, mieczyslaw, mothers-in-law, outlaw, shillinglaw, stanislaw, wardlaw, whitelaw, wroclaw
Mother-in-law sounds like:
maternal, matrimonial, matronly, metromail