Part I, Background -- Setting the Scene -- Learning from Others' Experience -- Part II, Using Conversation Analysis for Dialogue Modelling -- Patterns for Expert-Novice Chats -- Other-Initiated Self-repair with Linguistic Trouble Source -- Exposed Corrections -- Embedded Corrections -- Models of Learner-Error Corrections -- To Correct or Not to Correct -- Method Evaluation -- Part III, Model Validation and Future Directions -- Implementation of an Artificial Conversation Companion -- Future Research Directions -- Part IV, Supplements -- App. A, Data -- App. B, Coding Scheme for Polar Questions -- App. C, Examples -- References.