Identifying Teacher Questions Using Automatic Speech Recognition in Classrooms

We investigate automatic question detection from recordings of teacher speech collected in live classrooms. Our corpus contains audio recordings of 37 class sessions taught by 11 teachers. We automatically segment teacher speech into utterances using an amplitude envelope thresholding approach followed by filtering non-speech via automatic speech recognition (ASR). We manually code the segmented utterances as containing a teacher question or not based on an empirically-validated scheme for coding classroom discourse. We compute domain-independent natural language processing (NLP) features from transcripts generated by three ASR engines (AT&T, Bing Speech, and Azure Speech). Our teacher-independent supervised machine learning model detects questions with an overall weighted F1 score of 0.59, a 51% improvement over chance. Furthermore, the proportion of automatically-detected questions per class session strongly correlates (Pearson’s r = 0.85) with human-coded question rates. We consider our results to reflect a substantial (37%) improvement over the state-of-the-art in automatic question detection from naturalistic audio. We conclude by discussing applications of our work for teachers, researchers, and other stakeholders.