In linguistics, the topic (or theme) is informally what is being talked about, and the comment (rheme or focus) is what is being said about the topic. Although this general nature of topic-comment dichotomy is generally accepted, anything beyond that is a matter of great controversy.
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 probably responsible for bringing the ideas to Functional Grammar.
Note that in some categorizations, topic refers only to the contrastive theme and comment to the noncontrastive theme + rheme.
Contents [hide]
1 Definitions
2 Realization of topic/comment
3 See also
4 References
[edit] Definitions
The term "topic" can be defined in a number of different ways. Among the most common are
a.) the phrase in a clause that the rest of the clause is understood to be about,
b.) the phrase in a discourse that the rest of the discourse is understood to be about,
c.) a special position in a clause (often at the right or left-edge of the clause) where topics typically appear.
In an ordinary English sentence, the subject is normally the same as the topic. For example, the topic is emphasized in italics in the following sentences:
(1) The dog licked the little girl.
(2) The little girl was licked by the dog.
Although these sentences mean the same thing, they have different topics. The first sentence is about the dog, while the second is 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:
(3) As for the little girl, the dog licked her.
A distinction must be made between the clause-level topic and the discourse-level topic. Suppose we are talking about Mike's house:
(4) Mike's house was so comfortable and warm! He really didn't want to leave, but he couldn't afford the rent, you know. And it had such a nice garden in the back!
In the example, the discourse-level topic is established in the first sentence: it is Mike's house. In the following sentence, a new "local" topic is established on the sentence level: he (Mike). But the discourse-level topic is still Mike's house, which is why the last comment does not seem out of place.
[edit] 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.
English: intonation is the primary means, although word order (e.g., fronting of contrasted topics: Kim, I like.) and other syntactic (passivisation, clefting) or lexical means ("As for...", "Regarding...") are also employed.
Japanese: topic is marked with a special clitic postposition (は, -wa); see a presentation about this problem in Japanese [1].
So called free-word order languages (e.g. Russian, Czech, to a certain extent Chinese or German) use word-order as the primary means. Usually topic precedes focus. However, for example in Czech, both orders are possible. The order with comment sentence-initial is referred as subjective (V. Mathesius' term, as opposed to objective) and expresses certain emotional involvement. The two orders are distinguished by intonation.
Languages often show different kinds of grammar for sentences that introduce new topics and those that continue discussing previously established topics. When a sentence introduces a new topic for discussion, it is most likely to use one of the strategies mentioned in (b), or (c) above.
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, as mentioned in (a) above. In many languages, pronouns referring to previously established topics will show pro-drop.
[edit] See also
Topic-prominent language
Focus (linguistics)
Thematic equative
Topic particle
Predicate (grammar)