topiccomment

Topiccomment, or topic-comment structure, is a term in linguistics describing a sentence organization in which the topic is presented first, followed by a comment about the topic. The topic is typically given information or something the speaker assumes is known in the discourse, while the comment provides new information, evaluation, or predication about that topic. This structure contrasts with focus-based arrangements where the element in focus is the new information being highlighted.

Cross-linguistically, topic-comment patterns appear in many languages with flexible word order. Some languages use dedicated particles or clitics to mark the topic, such as the topic markers in Japanese, Korean, or Chinese constructions where a topic is introduced and the rest of the sentence comments on it. Other languages rely on prosody or left-peripheral positioning of topic phrases to signal the distinction between topic and comment. The topic often corresponds to the discourse given information, while the comment contributes new assertions about that information.

Historical background: The topic-comment idea is central to information structure and Functional Sentence Perspective, associated with the Prague School in the early 20th century, including Vilém Mathesius and Jan Firbas. In modern syntax and semantics, topic-comment is discussed as a way to model how discourse context shapes sentence form, sometimes analyzed in terms of evoked versus asserted content or as a fronted topic phrase.

Relation to subject and focus: The topic is not necessarily the grammatical subject; it is what the sentence is about. The comment often asserts something about the topic, and the distinction from focus helps explain why topics can be fronted even when the focal element remains elsewhere in the clause.

Applications: The concept informs linguistic analysis, language teaching, and natural language processing, particularly in discourse modeling, translation, and information-structuring tools.