Discourse markers do this by showing turns, joining ideas together, showing attitude, and generally controlling communication. Some people regard discourse markers as a feature of spoken language only.
Example
Words like 'actually', 'so', 'OK', 'right?' and 'anyway' all function as discourse markers as they help the speaker to manage the conversation and mark when it changes.
In the classroom
Discourse markers are an important feature of both formal and informal native speaker language. The skilful use of discourse markers often indicates a higher level of fluency and an ability to produce and understand authentic language.
Further links:
https://www.teachingenglish.org.uk/article/clil-a-lesson-framework
https://www.teachingenglish.org.uk/article/context-developing-activities