We are developing an AI-powered, web-based system to analyze the nonverbal communication (NVC) skills of EFL students in Japan. Teaching verbal communication (VC) skills is challenging due to typical student-to-teacher ratios of 40:1, with NVC requiring even more individualized instruction and feedback. In this case study, we focus on the AI-enhanced video analysis tool we are developing to support the final system. We analyze the facial expressions (perceived emotions and gaze/engagement) and body language (head and facial movements) of EFL students (aged 18–20) using standard webcams and correlate these data with online assessments from a diverse group of human judges. We conduct mock (simulated) online job interviews, as this method allows us to achieve two goals: 1) primarily collect data to improve the functionality of our NVC training system, and 2) secondarily provide students with feedback that can assist them in other online interview contexts, such as TOEFL, IELTS, and future academic or professional interviews. We are developing our final system in-house and will showcase our software methodology and its current developmental stage. Once complete, our system will enhance students' NVC skills by increasing their awareness, motivation, and self-efficacy, while improving their online interview performance.