topic (n.)

A term used in SEMANTICS and GRAMMAR as part of an alternative binary characterization of SENTENCE STRUCTURE to that traditionally found in the SUBJECT/PREDICATE distinction; the opposite term is COMMENT. The topic of a sentence is the entity (person, thing, etc.) about which something is said, whereas the further statement made about this entity is the comment. The usefulness of the distinction is that it enables general statements to be made about the relationships between sentences which the subject/predicate distinction (along with other contrasts of this type) obscures. The topic often coincides with the subject of a sentence (e.g. A visitor/ is coming to the door), but it need not (e.g. There’s the driver/ who gave you a lift), and, even when it is a subject, it need not come first in a sentence (e.g. John Smith my name is). It is sometimes referred to as the ‘psychological subject’. Some languages mark the topic of a sentence using PARTICLES (e.g. Japanese, Samoan). The topic/comment contrast is, however, sometimes difficult to establish, owing to the effects of INTONATION (which has a ‘competing’ INFORMATION-signalling function), and in many types of sentence the analysis is more problematic, such as in COMMANDS and QUESTIONS. Topicalization takes place when a CONSTITUENT is moved to the front of a sentence, so that it functions as topic, e.g. The answer I’ll give you in a minute.

The phrase topic sentence is used in traditional studies of the structure of paragraphs, to refer to the sentence which introduces the paragraph’s theme. Linguistic investigation of this and related notions is in its early stages, but TEXT analysis of paragraphs indicates that the SEMANTIC and SYNTACTIC complexities of paragraph structure are much greater than this simple judgement suggests.