A discourse marker is a word or a phrase that plays a role in managing the flow and structure of discourse. Since their main function is at the level of discourse (sequences of utterances) rather than at the level of utterances or sentences, discourse markers are relatively syntax-independent and usually do not change the truth conditional meaning of the sentence.[1] They can also indicate what a speaker is doing on a variety of different planes.[2] Examples of discourse markers include the particles oh, well, now, then, you know, and I mean, and the discourse connectives so, because, and, but, and or.[3] The term discourse marker was popularized by Deborah Schiffrin in her 1987 book Discourse Markers.[4]