Speculate rhymes with:
articulate, calculate, circulate, innoculate, inoculate, miscalculate, recalculate, accumulate, articulate, calculate, circulate, coagulate, copulate, depopulate, emulate, formulate, innoculate, inoculate, manipulate, miscalculate, overregulate, populate, recalculate, reformulate, regulate, reregulate, stimulate, stipulate, strangulate, tabulate
Speculate sounds like:
speciality, specialty, speckled, speculated