Postlethwait rhymes with:
postlewait, postlewaite, abbate, accentuate, apostate, candidate, chlorate, coarticulate, colgate, cremate, dehydrate, deregulate, desiccate, disassociate, discombobulate, dislocate, dissociate, elongate, exculpate, exfoliate, fugate, gionet, gradate, hallucinate, huguet, hungate, insinuate, insubstantiate, khanate, labate, lactate, maret, matriculate, modulate, newgate, onate, ovate, overpopulate, palpitate, paquet, perchlorate, phosphate, placate, postlewait, postlewaite, prevaricate, promulgate, prostrate, reallocate, rehydrate, relocate, reorientate, reprobate, tungate, vacate, vaccinate, validate, variegate, verret, vibrate, vindicate, violate, vociferate, zarate
Postlethwait sounds like:
postlewait, postlewaite, postulate