Congratulation rhymes with:
self-congratulation, self-congratulation, self-congratulation, self-congratulation, self-congratulation, self-congratulation, capitulation, self-congratulation, accumulation, adulation, annihilation, appellation, articulation, assimilation, calculation, cancellation, capitulation, coagulation, compilation, confabulation, consolation, constellation, correlation, demodulation, deregulation, desolation, distillation, emulation, escalation, exhalation, extrapolation, formulation, gastrulation, granulation, inhalation, innoculation, inoculation, installation, insulation, isolation, jubilation, manipulation, miscalculation, modulation, mutilation, oscillation, overpopulation, overregulation, ovulation, population, recalculation, regulation, reregulation, revelation, self-congratulation, simulation, speculation, stimulation, stipulation, strangulation, tabulation, tribulation, vacillation, ventilation, violation