Topic and comment

This article is about the sentence-level category topic; for the discourse-level category see Discourse topic; topic is also commonly referred to as theme; for theme in generative grammar, see theta role; for theme in semantics, see Thematic relation.

In linguistics, the topic, or theme, of a sentence is what is being talked about, and the comment (rheme or focus) is what is being said about the topic. That the information structure of a clause is divided in this way is generally agreed on, but the boundary between topic/theme and comment/rheme/focus depends on grammatical theory.

The difference between "topic" and grammatical subject is that topic is used to describe the information structure, or pragmatic structure of a clause and how it coheres with other clauses, whereas the subject is a purely grammatical category. Topic and subject must also be distinguished from actor (or agent), the "doer". In English clauses with a verb in the passive voice, for instance, the topic is typically the subject, while the agent may be omitted or may follow the preposition by. In some languages, word order and other syntactic phenomena are determined largely by the topic–comment (theme–rheme) structure. These languages are sometimes referred to as topic-prominent languages. Chinese and Japanese are often given as examples of this.

The distinction was probably first suggested by Henri Weil in 1844. Georg von der Gabelentz distinguished psychological subject (roughly topic) and psychological object (roughly focus). In the Prague school, the dichotomy, termed topic–focus articulation, has been studied mainly by Vilém Mathesius, Jan Firbas, František Daneš, Petr Sgall and Eva Hajičová. They have been concerned mainly by its relation to intonation and word-order. The work of Michael Halliday in the 1960s is responsible for developing linguistic science through his systemic functional linguistics model for English (see e.g. Halliday 1967–68, 1970)


The sentence- or clause-level "topic", or "theme", can be defined in a number of different ways. Among the most common are

In an ordinary English clause, the subject is normally the same as the topic/theme (example 1), even in the passive voice (where the subject is a patient, not an agent: example 2):

These clauses have different topics: the first is about the dog, and the second about the little girl.

In English it is also possible to use other sentence structures to show the topic of the sentence, as in the following:

The case of expletives is sometimes rather complex. Consider sentences with expletives (meaningless subjects), like:

In these examples the syntactic subject position (to the left of the verb) is manned by the meaningless expletive ("it" or "there"), whose sole purpose is satisfying the extended projection principle, and is nevertheless necessary. In these sentences the topic is never the subject, but is determined pragmatically. In (6) the topic is the whole proposition expressed by the sentence (i.e., the fact that it is raining). In (7) it is "some room". In (8) it is arguably the equality in length of the day and night in some day (rather than the day itself).

Realization of topic–comment

Different languages mark topics in different ways. Distinct intonation and word-order are the most common means. The tendency to place topicalized constituents sentence-initially ("topic fronting") is widespread. Again, linguists disagree on many details.

Languages often show different kinds of grammar for sentences that introduce new topics and those that continue discussing previously established topics.

When a sentence continues discussing a previously established topic, it is likely to use pronouns to refer to the topic. Topics of this sort show a tendency to be subjects. In many languages, pronouns referring to previously established topics will show pro-drop.

Realization of topic–comment in English

The topic/theme comes first in the clause, and is typically marked out by intonation as well.[1]

Realization of topic–comment in other languages

See also


  1. MAK Halliday (1994). An introduction to functional grammar, 2nd ed., Hodder Arnold: London, p. 37

Further reading

This article is issued from Wikipedia - version of the 11/27/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.