We can all speak and understand each other; do we need to investigate how?

Chapter 1 THE SENTENCE

Anything that is said in the act of communication is called an utterance. Most utterances are sentences, although there are some which are not sentences and are called non-sentence utterances. Thus utterances fall into two groups: sentences and non-sentence utterances.

Sentences may be regarded from the point of view of their structure and their communicative value.

1.1 Structural classification of sentences

From the point of view of their structure, sentences can be:

1. Simple or composite (compound and complex).

2. Complete or incomplete (elliptical).
3. Two-member (double-nucleus) or one-member (single-nucleus).

These three classifications are based on different approaches to the structural organisation of sentences and reflect its different aspects.

The difference between the simple sentence and the composite sentence lies in the fact that the former contains only one subject-predicate unit and the latter more than one. Subject-predicate units that form composite sentences are called clauses.
Honesty is the best policy. (one subject-predicate unit)
Still waters run deep. (one subject-predicate unit)
You can take a horse to the water, but you cannot make him drink, (two subject-predicate units, or two
clauses)
You never know what you can do till you try. (three subject-predicate units, or three clauses)

The difference between the compound and complex sentence lies in the relations between the clauses that constitute them

Complete and incomplete (or elliptical) sentences are distinguished by the presence or absence of word-forms in the principal positions of two-member sentences.
In a complete sentence both the principal positions are filled with word-forms.

When did you arrive?

I came straight here.

In an incomplete (elliptical) sentence one or both of the main posi­tions are not filled, but can be easily supplied as it is clear from the context what is missing.

Cheerful, aren’t you?

Ready?
Could’ve been professional.
Wrong again.

Elliptical sentences are typical of conversational English. One-member and two-member sentences are distinguished by the num­ber of principal parts (positions) they contain: two-member sentences have two main parts - the subject and the predicate, while one-member sen­tences have only one principal part, which is neither the subject nor the predicate.