Constituent: "a syntactic unit that functions as part of a larger unit within a sentence" (Finegan and Besnier: 525)
1. Single words
are constituents. (exceptions: certain contractions, certain possessives)
Complete sentences are constituents.
2. Any sequence of words which can be functionally replaced by a single word must be a constituent.
The man in the
is my brother. You were sick when I saw you.
Tom is my brother. You were sick yesterday.
A specific subcase of (2): any sequence of words which can be replaced by a proform is a constituent.
The woman with
won first prize. She won it.
Tommy studied hard for the test and Jane studied hard for the test too.
Tommy studied hard for the test and Jane did too.
3. Any sequence of words which can stand alone in answer to a question or conversely, any sequence of words which can be questioned as a unit is a constituent.
Why did John win?
Because he paid off the judges.
Who did John pay? The judges.
Where did he go? To Spain.
This does not merely argue that these are constituents in the ellipted answer form given above, but in the full sentence forms from which these are apparently derived:
because he paid off the judges.
John paid the judges.
John went to Spain.
4. Any sequence of words conjoined to an independently identifiable constituent is a constituent.
Mary helped the man in the green hat and Michael.
Since Michael is a single word, and so a constituent, and it is can be conjoined to the man in the green hat, then the man in the green hat must be a constituent.
How can we tell that Michael is conjoined to the man in the green hat and not to hat or the green hat or man in the green hat? Compare Mary helped Michael and the man in the green hat with the sentence above. Notice that it is possible to change the order of Michael and the man in the green hat. It is not possible to change the order of hat and Michael and get a grammatical sentence: *Mary helped the man in the green Michael and hat. Similarly *Mary helped the man in Michael and the green hat and Mary helped the Michael and man in the green hat are ungrammatical. Coordinate conjunction joins structurally parallel units; any order of the conjuncts should produce a grammatical sentence.
As a corollary, conjoined units form a constituent: Mary helped the man in the green hat and Michael as can be demonstrated by other tests:
Mary helped them.
Who did Mary help? The man in the green hat and Michael. (question)
5. Any sequence of words which can be moved as a unit and still produce a grammatical sentence with the same meaning is a constituent.
I worked on the
ancient text with great care.
With great care I worked on the ancient text.
Mary put the books and the new computer into her car.
Mary put into her car the books and the new computer.
6. The tests in (1-5) are all one-way, positive tests: If you can't find a good sentence where the test works, that does not prove that the sequence of words in question is not a constituent. If you can find a good sentences where one of these tests works (or better where several of them do), that gives strong evidence that the sequence of words is a constituent. There is one way demonstrate that a continuous sequence of words does not form a constituent: A sequence of words cannot be a constituent if its parts are part of other constituents which are not subunits of the same constituent. In other words, in the sentence The man stole the money we can demonstrate that the man is a constituent; stole the money is a constituent; and the money is a constituent.
He stole the money.
Who stole the money? The man did.
The man stole it.
Who stole the money? The man.
What did the man do? Stole the money.
What did he steal? The money.
Tom and the man stole the money.
The man stole the money and disappeared.
The man stole furniture and the money.
Given that these are the constituents of this sentence, man stole, for example, cannot be a constituent. Since man is a constituent of a larger constituent that does not include stole and stole is part of a larger constituent that does not include man; they cannot together form a constituent. What other sequences of words in this sentence cannot form a constituent?