The deliberate omission of one or more words in the sentence for definite stylistic purpose is called the stylistic device of ellipsis. E.g.:
"The ride did Ma good. Rested her." (D. Carter)
The second sentence in the above example is elliptical, as the subject of the sentence is omitted.
The omission of some parts of the sentence is an ordinary and typical feature of the oral type of speech. In belles-lettres style the peculiarities of the structure of the oral type of speech are partially reflected in the speech of characters:
These are normal syntactical structures in the spoken language.
The omission of some parts of the sentence in the above example reflects the informal and careless character of speech.
Some parts of the sentence may be omitted due to the excitement of the speaker. Such cases of omission of some parts of the sentence in the speech of characters reflecting the natural structure of the oral type of speech are not considered a stylistic device:
Got a letter? Enjoy your holiday? My best wishes to your father! Had a good time.
The stylistic device of ellipsis is used in the author's narration and in the represented speech to add emotional colouring or to underline the most important information of the utterance:
"Serve him right; he should arrange his affairs better! So any respectable Forsyte." (J.Galsworthy)
In the above example the predicate is omitted and the reader has to supply what is missing. The stylistic device of ellipsis makes the sentence laconic and prominent.
The stylistic device of ellipsis used in represented inner speech creates a stylistic effect of the natural abruptness:
"It would have been a good idea to bring along one of Doc's new capsules. Could have gone into a drug store and asked for a glass of water and taken one". (D. Carter)
It is difficult to draw a line of demarcation between elliptical sentences and one-member sentences.
One-member sentences are often used to present the background of the action as in this example:
"Men, palms, red plush seats, while marble tables, waiters in the aprons. Miss Moss walked through them all". (Mansfield)
One-member sentence may be used to heighten the emotional tension of the narration or to single out the character's or the author's attitude towards what is happening.
The most widely used patterns of elliptical constructions are the following: The simple verbal predicate is omitted. In English parallel constructions this omission shows the similar or opposed nature of the phenomena: His face was rather rugged, the cheeks thin;
"He told her his age,twenty-four; his weight, a hundred and forty pounds; his place of residence, not far away". (J. Galsworthy)
The deliberate omission of some parts of the sentence is met in the written type of speech - especially in belles- lettres style. Very often ellipsis occurs in poetry: