Adults and infants make use of both auditory and visual information in speech perception. The available visual cues include oral-articulatory movements (e.g., lip movements), as well as non-verbal gestures (e.g., head-movements). The present project seeks to investigate the role of visual cues as an aid for auditory prosody in speech segmentation and in bootstrapping syntactic development, topic that remains as yet unexplored. The present project focuses on a type of prosodic information, i.e., the acoustic realization of phrasal prominence, which has been proposed to potentially allow prelexical infants bootstrap the basic word order of the target language, a major syntactic property of natural languages. Phrasal prominence correlates systematically with word order, i.e., it is realized by means of pitch changes in OV languages, and changes in duration in VO languages. The series of experiments here presented aim to: (i) identify and measure the visual cues—facial gestures—that potentially accompany the prosodic cues—changes in pitch and duration—correlated with word order differences, and (ii) examine whether visual cues modulate or determine the segmentation preferences of adult and infant monolinguals and bilinguals of an unknown language that additionally contains prosodic cues. In a series of artificial language learning experiments participants will be familiarized with artificial languages that contain either matching or mismatching auditory and visual cues—which will displayed by means of a computer-animated avatar—and will be subsequently tested on their segmentation preferences. This research will advance our understanding of the role of visual facial information in speech processing, as well as of the cognitive mechanisms involved in the acquisition of syntax.