Sentence

A sentence (/sentəns/) is a string of words, usually written, that typically contains one complete idea. Sentences function as the largest grammar unit of written language, such as written English. The term itself is somewhat difficult to define technically, but most people are aware from their own extensive experience what broadly constitutes a sentence.

In modern linguistics, a sentence is usually considered written language, in contrast to an utterance of speech.

Meaning

As a component of language, a sentence exists within a particular context. It may be difficult to determine the meaning of a decontextualised sentence.

Function

Sentences exist at the boundary between grammar and discourse. A sentence is considered the largest type of grammatical unit. Some modern grammarians however, noting the difficulty in defining a sentence in pure grammatical terms, argue that a sentence is the smallest type of discourse unit.

Sentences break text up into comprehensible chunks. A good writing style is to restrict each sentence to one idea, as this contributes to intrasentence cohesion. Conversely, sentences containing more than one idea may be grammatical, but are often awkward to read.

Multiple sentences together form paragraphs and well-written paragraphs possess intersentence cohesion. Often sequential sentences follow a topic and comment / rheme and theme pattern.

Types of sentence

By function

There are broadly three types of sentence, each of which is typically expressed by using a different grammatical mood:

• Statements - which usually use the declarative mood. This is the default type.
• Questions - which usually use the interrogative mood.
• Commands - which usually use the imperative mood.

Major sentences

The prototypical sentence is called a major sentence and consists of a subject and a predicate; it has a single main clause and may have additional subordinate clauses. In a command, using the imperative mood, the subject is usually an implied subject.

Deviations from this formula are called minor sentences and often accepted if they convey literary or poetic qualities.

Orthography

Orthographically, sentences typically employ standardised punctuation rules. They start with a capital letter and end with a terminal mark (especially a full stop). An orthographic sentence can be defined purely in terms of orthography. Some people break these conventions, particularly in informal writing.

When reading out loud, punctuation marks the prosodic features of sentences.

Complexity

Sentences have sentence complexity, depending on:

• the number of clauses they contain
• the syntax of clauses they contain
• the relationship between clauses they contain

A sentence that has no mistakes in grammar is called a well-formed sentence.

Pedagogy

Sentences are taught to learners both as grammatical units, and discourse units, to improve writing and comprehension.

Lessons in writing revolve around topics such as:

• correct punctuation of sentences
• writing strategies centered on sentence content

Sentences, considered as extensions of clauses, shape grammar lessons too. Those lessons revolve around topics such as:

• the syntax of clauses and the relationships between them in sentences
• the differences between sentences and questions
• the form of different types of statements

Foreign language learners are often encouraged to “speak in full sentences,” to demonstrate understanding of the underlying grammatical form.

Further reading

• The entry in the Oxford Dictionary of English Grammar is pretty good.