The current study evaluated the effects of a stimulus-stimulus pairing procedure intended to increase spontaneous vocalizations of a young child diagnosed with autism. A multiple-baseline design across two target phonemes was used to evaluate the effects of the pairing procedure on the frequency of phonemes uttered by the participant. Data were collected during presession, postsession, and follow-up periods across three conditions: Baseline, Control, and Pairing. During the Pairing conditions, a target phoneme was repeatedly vocalized by the experimenter and was systematically paired with preferred stimuli. Results from postsession observations following the pairing condition evidenced no increase in the target sounds. Practical and theoretical implications of the results are discussed.