This project aims to address the limitations of qualitative descriptions of nonverbal communication by developing automated measurement tools to enable data-driven, objective characterizations of coordination of nonverbal communication. Participants (ages 1-4) complete a play-based assessment and a semi-structured assessment of nonverbal communication, which are recorded using multiple cameras as well as wearable accelerometers. Our collaborators at Georgia University of Technology, led by Dr. James Rehg, will develop a methodology and an associated set of software tools to convert data into computational models that quantify the fine-grained details of timing and coordination of nonverbal communication behaviors. Participants will return a year after their initial visit, allowing us to evaluate the extent to which the computational models of nonverbal communication can predict later language outcomes.