  Existing English-teaching chatbots rarely incorporate empathy explicitly in
their feedback, but empathetic feedback could help keep students engaged and
reduce learner anxiety. Toward this end, we propose the task of negative
emotion detection via audio, for recognizing empathetic feedback opportunities
in language learning. We then build the first spoken English-teaching chatbot
with adaptive, empathetic feedback. This feedback is synthesized through
automatic prompt optimization of ChatGPT and is evaluated with English
learners. We demonstrate the effectiveness of our system through a preliminary
user study.
