*Introduction* MyST (My Science Tutor) Children's Conversational Speech was developed by Boulder Learning Inc. It is comprised of approximately 470 hours of English speech from 1371 students in grades 3-5 conversing with a virtual science tutor in eight areas of science instruction, along with transcripts and a pronunciation dictionary. Data was collected in two phases between 2008 and 2017. In both phases, spoken dialogs with the virtual tutor were aligned to classroom instruction using the Full Option Science System (FOSS) system, a research-based science curriculum for grades K-8. The eight FOSS science modules represented in this data set consisted of an average of 16 small-group classroom science investigations. Following the investigations, students conversed with the virtual science tutor for 15-20 minutes. The tutor asked open-ended questions about media presented on-screen, and students produced spoken answers. *Data* Speech data was collected in 10,496 sessions for a total of 227,567 utterances. Approximately 45% of those utterances (102,433) were transcribed. All data collected in Phase I was transcribed using rich transcription guidelines; data collected in Phase II was partially transcribed using a reduced version of those guidelines. The transcription guidelines are included in this release. Data is divided into development, test, and train partitions for use with ASR systems Speech is presented in single channel, 16kHz, 16-bit flac compressed wav format. Transcripts are UTF-8 encoded plain text.

Creator(s)

Sameer Pradhan

Ronald Allan Cole

Wayne Ward

Distributor(s)

Linguistic Data Consortium

Right Holder(s)

Portions © 2021 Boulder Learning Inc., © 2021 Trustees of the University of Pennsylvania