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.