sentence

A sentence is a linguistic unit consisting of one or more words that are grammatically linked. A sentence can include words grouped meaningfully to express a statement, question, exclamation, request, command or suggestion. A sentence is a set of words that in principle tells a complete thought, although it may make little sense taken in isolation out of context. Typically a sentence contains a subject and predicate. A sentence can also be defined purely in orthographic terms, as a group of words starting with a capital letter and ending in a full stop. For instance, the opening of Charles Dickens' novel Bleak House begins with the following three sentences:

London. Michaelmas term lately over, and the Lord Chancellor sitting in Lincoln's Inn Hall. Implacable November weather.

The first sentence involves one word, a proper noun. The second sentence has only a non-finite verb (although using the definition given above, e.g. "Chancellor sitting in Lincoln's Inn Hall." would be a sentence by itself). The third is a single nominal group. Only an orthographic definition encompasses this variation.

As with all language expressions, sentences might contain function and content words and contain properties distinct to natural language, such as characteristic intonation and timing patterns.

Sentences are generally characterized in most languages by the inclusion of a finite verb, e.g. "The quick brown fox jumps over the lazy dog".

Components of a sentence

Clauses

A clause typically contains at least a subject noun phrase and a finite verb. While the subject is usually a noun phrase, other kinds of phrases (such as gerund phrases) work as well, and some languages allow subjects to be omitted. There are two types of clauses: independent and subordinate (dependent). An independent clause is a complete sentence in itself, although it may not express a complete thought: for example, They did it. A subordinate clause is not a complete sentence: for example, because I have no friends. See also copula for the consequences of the verb to be on the theory of sentence structure.

A simple complete sentence consists of a single clause. Other complete sentences consist of two or more clauses (see below).

Classification

By structure

One traditional scheme for classifying English sentences is by clause structure, the number and types of clauses in the sentence with finite verbs.

• A simple sentence consists of a single independent clause with no dependent clauses.
• A compound sentence consists of multiple independent clauses with no dependent clauses. These clauses are joined together using conjunctions, punctuation, or both.
• A complex sentence consists of one independent clause and at least one dependent clause.
• A complex-compound sentence (or compound-complex sentence) consists of multiple independent clauses, at least one of which has at least one dependent clause.

By purpose

Sentences can also be classified based on their purpose:

• A declarative sentence or declaration, the most common type, commonly makes a statement: "I have to go to work."
• An interrogative sentence or question is commonly used to request information — "Do I have to go to work?" — but sometimes not; see rhetorical question.
• An exclamatory sentence or exclamation is generally a more emphatic form of statement expressing emotion: "I have to go to work!"
• An imperative sentence or command tells someone to do something (and if done strongly may be considered both imperative and exclamatory): "Go to work." or "Go to work!"

Major and minor sentences

A major sentence is a regular sentence; it has a subject and a predicate. For example: "I have a ball." In this sentence one can change the persons: "We have a ball." However, a minor sentence is an irregular type of sentence. It does not contain a main clause. For example, "Mary!" "Precisely so." "Next Tuesday evening after it gets dark.". Other examples of minor sentences are headings (e.g. the heading of this entry), stereotyped expressions ("Hello!"), emotional expressions ("Wow!"), proverbs, etc. These can also include nominal sentences like "The more, the merrier". These mostly omit a main verb for the sake of conciseness, but may also do so in order to intensify the meaning around the nouns: this type of sentence is often found in poetry and catchphrases.

Sentences that comprise a single word are called word sentences, and the words themselves sentence words.

Sentence length

After a slump in interest, sentence length came to be studied in the 1980s, mostly "with respect to other syntactic phenomena".

One definition of the average sentence length of a prose passage is the ratio of the number of words to the number of sentences. The textbook Mathematical linguistics, by András Kornai, suggests that in "journalistic prose the median sentence length is above 15 words". The average length of a sentence generally serves as a measure of sentence difficulty or complexity. In general, as the average sentence length increases, the complexity of the sentences also increases.

Another definition of "sentence length" is the number of clauses in the sentence, while the "clause length" is the number of phones.

Research by Erik Schils and Pieter de Haan (by sampling five texts) showed that two adjacent sentences are more likely to have similar lengths than two non-adjacent sentences, and almost certainly have similar length when in a work of fiction. This countered the theory that "authors may aim at an alternation of long and short sentence". Sentence length, as well as word difficulty, are both factors in the readability of a sentence. However, other factors, such as the presence of conjunctions, have been said to "facilitate comprehension considerably".

See also

• Grammatical polarity
• Inflectional phrase
• Periodic sentence
• Sentence arrangement
• Sentence function
• T-unit

External links

• Basic Sentence Structures
• The definition and meaning of the words "idea", "thought" and "sentence".
• Sentence Variety: Sentence Types
• The Sentence: A Group of Words Expressing a Meaning
• "The Book-Length Sentence" and "The Art of the Very Long Sentence", a history of very long sentences. Ed Park, New York Times Book Review, December 24, 2010 and January 3, 2011 (respectively).
• phraseup* - A writing assistant that helps with completing sentences by finding the missing words we can't recall.
• Fraze.it - A search engine for sentences and phrases. Supports six languages, filtered by form, zone, context, etc.