Substantiation rhymes with:
abbreviation, affiliation, alleviation, appreciation, appropriation, association, aviacion, aviation, conciliation, creation, d'aviation, delineation, denunciation, depreciation, deviation, differentiation, dissociation, exfoliation, expatriation, expropriation, foliation, glaciation, humiliation, initiation, instantiation, irradiation, mediation, misappropriation, miscreation, negotiation, nucleation, procreation, pronunciation, radiation, reaffiliation, reconciliation, recreation, remediation, renegotiation, renunciation, repatriation, repudiation, retaliation, variation