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.
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) It may be a simple phrase, but it
conveys enough meaning to imply a clause,
even if it is not explicit; for example, "Two"
as a sentence (in answer to the question "How
many were there?") implies the clause "There
were two."
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.In
the teaching of writing skills (composition
skills), students are generally required to
express (rather than imply) the elements of
a sentence, leading to the schoolbook definition
of a sentence as one that must [explicitly]
include a subject and a verb.
For example, in second-language acquisition,
teachers often reject one-word answers that
only imply a clause, commanding the student
to "give me a complete sentence," by which
they mean an explicit one.
As with all language expressions, sentences
might contain function and content words and
contain properties 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."
== 
Typical associates ==
=== Clauses ===
In non-functional linguistics, a simple complete
sentence consists of a single clause.
In functional linguistics, a sentence is typically
associated with a clause and a clause can
be either a clause simplex or a clause complex.
A clause is a clause simplex if it represents
a single process going on through time and
it is a clause complex if it represents a
logical relation between two or more processes
and is thus composed of two or more clause
simplexes.
A clause (simplex) typically contains a predication
structure with a subject noun phrase and a
finite verb.
Although 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.
In the examples below, the subject of the
outmost clause simplex is in italics and the
subject of boiling is in square brackets.
Notice that there is clause embedding in the
second and third examples.
[Water] boils at 100 degrees Celsius.
It is quite interesting that [water] boils
at 100 degrees Celsius.
The fact that [water] boils at 100 degrees
Celsius is quite interesting.There are two
types of clauses: independent and non-independent/interdependent.
An independent clause realises a speech act
such as a statement, a question, a command
or an offer.
A non-independent clause does not realise
any act.
A non-independent clause (simplex or complex)
is usually logically related to other non-independent
clauses.
Together they usually constitute a single
independent clause (complex).
For that reason, non-independent clauses are
also called interdependent.
For instance, the non-independent clause because
I have no friends is related to the non-independent
clause I don't go out in I don't go out, because
I have no friends.
The whole clause complex is independent because
it realises a statement.
What is stated is the causal nexus between
having no friend and not going out.
When such a statement is acted out, the fact
that the speaker doesn't go out is already
established, therefore it cannot be stated.
What is still open and under negotiation is
the reason for that fact.
The causal nexus is represented by the independent
clause complex and not by the two interdependent
clause simplexes.
See also copula for the consequences of the
verb to be on the theory of sentence structure.
== 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 compound–complex sentence (or complex–compound
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!"
An "instructive sentence" or instruction is
used to provide information on what something
is or how something can be done.
=== Major and minor sentences ===
A major sentence is a regular sentence; it
has a subject and a predicate, e.g. "I have
a ball.".
In this sentence, one can change the persons,
e.g.
"We have a ball.".
However, a minor sentence is an irregular
type of sentence that does not contain a main
clause, e.g. "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.Sentences
that comprise a single word are called word
sentences, and the words themselves sentence
words.
== Length ==
The 1980s saw a renewed surge in interest
in sentence length, primarily in relation
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,
whereas the "clause length" is the number
of phones in the clause.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 a similar
length when in a work of fiction.
This countered the theory that "authors may
aim at an alternation of long and short sentences."
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
== References ==
