Producing and processing speech involves complex feedbackloops of sensory and motor signals. Vocal sounds are par-tially processed as a movement affordance, allowing us to learnspeaking patterns through imitation, which can be beneficialfor language learning. In this study, we examine this pro-cess as a type of social embodiment illusion — the blurringof boundaries between self and other. Participants performedan altered version of a theatrical game called the ‘one-voiceexpert’, where they improvised speech in same-gender dyads.Unlike previous studies, we looked separately at the effectsof simultaneousness (‘speaking at the same time’) and syn-chronicity (‘saying the same thing’). These two variables werefound to influence vocal characteristics and self-voice recog-nition in a distinct way, with synchronicity leading to strongerpitch adaptation and simultaneousness to suppression of pho-netic convergence. We conclude that linking embodiment pro-cesses to joint speech in real world social interactions could bea promising new conceptual framework, with possible applica-tions for language learning.