Editing Topic and comment (section)

== Definitions and examples ==

The sentence- or clause-level "topic", or "theme", can be defined in a number of different ways. Among the most common are
*the phrase in a clause that the rest of the clause is understood to be about,
*a special position in a clause (often at the right or left-edge of the clause) where topics typically appear.

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):
#''The dog'' bit the little girl.
#''The little girl'' was bitten by the dog.

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:
*''As for the little girl'', the dog bit her.
*''It'' was the little girl ''that the dog bit.''

The case of [[Expletive (linguistics)|expletives]] is sometimes rather complex. Consider sentences with expletives (meaningless subjects), like:

*It is raining.
*There is some room in this house.
*There are two days in the year in which the day and the night are equal in length.

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 [[Pragmatics|pragmatically]]. In all these cases, the whole sentence refers to the comment part.<ref>Michael Gotze, Stephanie Dipper, and Stavros Skopeteas. 2007. Information Structure in Cross-Linguistic Corpora: Annotation Guidelines for Phonology, Morphology, Syntax, Semantics, and Information Structure. Interdisciplinary Studies on Information Structure (ISIS), Working papers of the SFB 632, Vol. 7.</ref>

The relation between topic/theme and comment/rheme/focus should not be confused with the topic-comment relation in [[Rhetorical structure theory|Rhetorical Structure Theory]]-Discourse [[Treebank]] (RST-DT corpus) where it is defined as "a general statement or topic of discussion is introduced, after which a specific remark is made on the statement or topic". For example: "[As far as the pound goes,] [some traders say a slide toward support at 1.5500 may be a favorable development for the dollar this week.]"<ref>L. Carlson and D. Marcu, “Discourse tagging reference manual,” ISI Technical Report ISI-TR-545, vol. 54, 2001.</ref><ref>L. Ermakova and J. Mothe. 2016. Document re-ranking based on topic-comment structure. In X IEEE International Conference RCIS, Grenoble, France, June 1–3, 2016. 1–10.</ref>