topicandcomment

Topic and comment refers to a basic information-structure concept in linguistics and discourse analysis. In this framework, a sentence is analyzed as having a topic—the part of the sentence that identifies what is being discussed—and a comment, which provides information about that topic. The topic establishes the discourse context, while the comment supplies new or additional information about it.

In practice, the topic is often placed at the beginning of a sentence or marked by a discourse particle, intonation, or a grammatical marker. English can express topic structure through fronting or phrasing, as in “As for the weather, it’s sunny today.” In languages with explicit topic marking, such as Japanese, the topic is often indicated by particles like wa: “Watashi wa gakusei desu,” meaning “As for me, I am a student.” The remaining material then serves as the comment about the topic.

Topic and comment are related to, but distinct from, subject and predicate. The topic is not always the grammatical subject; it is the element under discussion, which can influence what counts as the focus of the sentence. The concepts are central to the broader idea of given/new information and to the theory of theme and rheme (also called topic and comment) in the Prague School of linguistics.

The notion is widely used in discourse analysis, typology, and natural language processing to model information structure, coherence, and how languages manage what listeners already know versus what is being introduced.