In general, the subject matter described in this disclosure can be embodied in methods, systems, and program products for engaging in interactive sessions between computerized devices and participants. The method includes receiving user input that interacts with user controls to specify, for each respective content item in a plurality of content items, a text spelling and an audio recording. The method includes receiving user input that selects a set of user-selected content items from among the plurality of content items for inclusion as part of the first interactive exercise, and assigns an order to the user-selected content items. The computing system presents the selected content items in the user-selected order, receives user input that inputs the respective content items, and determines whether the user input matches the content item.