Development of vocalizations in early learners with autism is critical to the acquisition of verbal behavior and other important life skills. The purpose of the present studies was to (1) evaluate the efficiency and efficacy of Stimulus-Stimulus Pairing (SSP) and standard Echoic Training (ET) procedures for the development and onset of verbal behavior in early learners with ASD to improve early intervention efficiency and (2) elucidate predictive characteristics or variables for the effective use of SSP. The present studies were comprised of a multiple-baseline (across behaviors) experimental design buttressed within a reversal design, also known more broadly as within-subject controlled experimental designs. It was found that SSP can have a greater treatment efficacy than ET, but any efficacy advantage is transitory. Shifting an SSP treatment to direct reinforcement contingencies once vocalizations are produced are likely the most effective strategy. SSP produces discrepant effects across learners, thus highlighting the need to assess a learner’s characteristics and assumed reinforcer effectiveness. It was also found that higher-functioning learners will benefit more greatly from ET as opposed to SSP.