Topic and comment

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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. This division into old vs. new content is called information structure. It is generally agreed that clauses are divided into topic vs. comment, but in certain cases the boundary between them depends on which specific grammatical theory is being used to analyze the sentence.


Topic, which is defined by pragmatic considerations, is a distinct concept from grammatical subject, which is defined by syntax. In any given sentence these may be the same, but they need not be. For example, in the sentence "As for the little girl, the dog bit her", the subject is "the dog" but the topic is "the little girl".

Topic and subject are also distinct concepts from agent (or actor)—the "doer", which is defined by semantics. 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. For example, in the sentence "The little girl was bitten by the dog", "the little girl" is the subject and the topic, but "the dog" is the agent.

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. Korean and Japanese are often given as examples of this.

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

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 all these cases, the whole sentence refers to the comment part. [1]

The relation between topic/theme and comment/rheme/focus should not be confused with the topic-comment relation in 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.]" [2] [3]

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. Topic fronting refers to placing the topic at the beginning of a clause regardless whether it is marked or not. [4] 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. Such topics tend to be subjects. In many languages, pronouns referring to previously established topics will show pro-drop.

In English

The topic/theme comes first in the clause, and is typically marked out by intonation as well. [5]

In other languages

Practical applications

The main application of the topic-comment structure is in the domain of speech technology, especially the design of embodied conversational agents (intonational focus assignment, relation between information structure and posture and gesture). [6] There were some attempts to apply the theory of topic/comment for information retrieval [7] and automatic summarization. [8]


The distinction between subject and topic was probably first suggested by Henri Weil in 1844. [9] He established the connection between information structure and word order. 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, [10] Jan Firbas, František Daneš, Petr Sgall and Eva Hajičová. They have been concerned mainly by its relation to intonation and word-order. Mathesius also pointed out that the topic does not provide new information but connects the sentence to the context. The work of Michael Halliday in the 1960s is responsible for developing linguistic science through his systemic functional linguistics model for English. [11]

See also

Related Research Articles

Functional linguistics is an approach to the study of language caracterized by taking systematically into account the speaker's and the hearer's side, and the communicative needs of the speaker and of the given language community. It is contrasted with linguistic formalism, which instead attempts to isolate syntax and consider it autonomously from meaning. Both functionalism and formalism spawned from the 1920s-1930s from Ferdinand de Saussure's systematic structuralist approach to language (1916).

Michael Halliday

Michael Alexander Kirkwood Halliday was an English-born linguist who developed the internationally influential systemic functional linguistics (SFL) model of language. His grammatical descriptions go by the name of systemic functional grammar. Halliday described language as a semiotic system, "not in the sense of a system of signs, but a systemic resource for meaning". For Halliday, language was a "meaning potential"; by extension, he defined linguistics as the study of "how people exchange meanings by 'languaging'". Halliday described himself as a generalist, meaning that he tried "to look at language from every possible vantage point", and has described his work as "wander[ing] the highways and byways of language". But he said that "to the extent that I favoured any one angle, it was the social: language as the creature and creator of human society".

In linguistics, syntax is the set of rules, principles, and processes that govern the structure of sentences in a given language, usually including word order. The term syntax is also used to refer to the study of such principles and processes. The goal of many syntacticians is to discover the syntactic rules common to all languages.

Systemic functional grammar

Systemic functional grammar (SFG) is a form of grammatical description originated by Michael Halliday. It is part of a social semiotic approach to language called systemic functional linguistics. In these two terms, systemic refers to the view of language as "a network of systems, or interrelated sets of options for making meaning"; functional refers to Halliday's view that language is as it is because of what it has evolved to do. Thus, what he refers to as the multidimensional architecture of language "reflects the multidimensional nature of human experience and interpersonal relations."

Clause Smallest grammatical unit that can express a complete proposition

In language, a clause is a part of the sentence that constitutes or comprises a predicate. A typical clause consists of a subject and a predicate, the latter typically a verb phrase, a verb with any objects and other modifiers. However, the subject is sometimes not said or explicit, often the case in null-subject languages if the subject is retrievable from context, but it sometimes also occurs in other languages such as English.

The subject in a simple English sentence such as John runs, John is a teacher, or John was run over by a car, is the person or thing about whom the statement is made, in this case John. Traditionally the subject is the word or phrase which controls the verb in the clause, that is to say with which the verb agrees. If there is no verb, as in John - what an idiot!, or if the verb has a different subject, as in John - I can't stand him!, then 'John' is not considered to be the grammatical subject, but can be described as the topic of the sentence.

Vilém Mathesius Czech linguist, literature historian and science writer

Vilém Mathesius was a Czech linguist, literary historian and co-founder of the Prague Linguistic Circle. He is considered one of the founders of structural functionalism in linguistics.

In linguistics, word order typology is the study of the order of the syntactic constituents of a language, and how different languages employ different orders. Correlations between orders found in different syntactic sub-domains are also of interest. The primary word orders that are of interest are

A cleft sentence is a complex sentence that has a meaning that could be expressed by a simple sentence. Clefts typically put a particular constituent into focus. In spoken language, this focusing is often accompanied by a special intonation.

In non-functional linguistics, a sentence is a textual unit consisting of one or more words that are grammatically linked. In functional linguistics, a sentence is a unit of written texts delimited by graphological features such as upper case letters and markers such as periods, question marks, and exclamation marks. This notion contrasts with a curve, which is delimited by phonologic features such as pitch and loudness and markers such as pauses; and with a clause, which is a sequence of words that represents some process going on throughout time. This entry is mainly about sentence in its non-functional sense, though much work in functional linguistics is indirectly cited or considered such as the categories of speech act theory.

In generative grammar, a theta role or θ-role is the formal device for representing syntactic argument structure—the number and type of noun phrases—required syntactically by a particular verb. For example, the verb put requires three arguments.

In syntax, dislocation is a sentence structure in which a constituent, which could otherwise be either an argument or an adjunct of the clause, occurs outside the clause boundaries either to its left or to its right. In this English example They went to the store, Mary and Peter the dislocation occurs to the right.

Focus is a grammatical category that determines which part of the sentence contributes new, non-derivable, or contrastive information. Focus is related to information structure. Contrastive focus specifically refers to the coding of information that is contrary to the presuppositions of the interlocutor.

In linguistics, intonation is variation in spoken pitch when used, not for distinguishing words as sememes, but, rather, for a range of other functions such as indicating the attitudes and emotions of the speaker, signalling the difference between statements and questions, and between different types of questions, focusing attention on important elements of the spoken message and also helping to regulate conversational interaction.

Jan Firbas

Jan Firbas, was a Czech linguist and a prominent representative of the Prague School of linguistics.

In linguistics, inversion is any of several grammatical constructions where two expressions switch their canonical order of appearance, that is, they invert. There are several types of subject-verb inversion in English: locative inversion, directive inversion, copular inversion, and quotative inversion. The most frequent type of inversion in English is subject–auxiliary inversion in which an auxiliary verb changes places with its subject; it often occurs in questions, such as Are you coming?, with the subject you is switched with the auxiliary are. In many other languages, especially those with a freer word order than English, inversion can take place with a variety of verbs and with other syntactic categories as well.

Thematic equative

In systemic functional grammar, a thematic equative is a thematic resource in which two or more separate elements in a clause are grouped together to form a single constituent of the theme-plus-rheme structure. An example of this is:

In linguistics, information structure, also called information packaging, describes the way in which information is formally packaged within a sentence. This generally includes only those aspects of information that “respond to the temporary state of the addressee’s mind”, and excludes other aspects of linguistic information such as references to background (encyclopedic/common) knowledge, choice of style, politeness, and so forth. For example, the difference between an active clause and a corresponding passive is a syntactic difference, but one motivated by information structuring considerations. Other structures motivated by information structure include preposing and inversion.

A syntactic expletive is a form of expletive: a word that in itself contributes nothing to the semantic meaning of a sentence, yet does perform a syntactic role. Expletive subjects in the form of dummy pronouns are part of the grammar of many non-pro-drop languages such as English, whose clauses normally require overt provision of subject even when the subject can be pragmatically inferred.. Consider this example:

In linguistics, functional sentence perspective (FSP) is a theory describing the information structure of the sentence and language communication in general. It has been developed in the tradition of the Prague School of Functional and Structural Linguistics together with its sister theory, Topic-Focus Articulation.


  1. 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.
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Further reading