Detection of Listener Uncertainty in Robot-Led Second Language Conversation Practice

Uncertainty is a frequently occurring affective state that learners experience during the acquisition of a second language. This state can constitute both a learning opportunity and a source of learner frustration. An appropriate detection could therefore benefit the learning process by reducing cognitive instability. In this study, we use a dyadic practice conversation between an adult second-language learner and a social robot to elicit events of uncertainty through the manipulation of the robot's spoken utterances (increased lexical complexity or prosody modifications). The characteristics of these events are then used to analyze multi-party practice conversations between a robot and two learners. Classification models are trained with multimodal features from annotated events of listener (un)certainty. We report the performance of our models on different settings, (sub)turn segments and multimodal inputs.