The present studies explored the role of prosody in motivating others, and applied self-determination theory (Ryan & Deci, 2000) to do so. Initial studies describe patterns of prosody that discriminate motivational speech. Autonomy support was expressed with lower intensity, slower speech rate and less voice energy in both motivationally laden and neutral (but motivationally primed) sentences. In a follow-up study, participants were able to recognize motivational prosody in semantically neutral sentences, suggesting prosody alone may carry motivational content. Findings from subsequent studies also showed that an autonomy-supportive as compared with a controlling tone facilitated positive personal (perceived choice and lower perceived pressure, well-being) and interpersonal (closeness to others and prosocial behaviors) outcomes commonly linked to this type of motivation. Results inform both the social psychology (in particular motivation) and psycho-linguistic (in particular prosody) literatures and offer a first description of how motivational tone alone can shape listeners’ experiences.