This page contains some representative tests, but it is by no means exhaustive.
Syntactic functional criteria
to identify constituents:
- Constituents as a single syntactic functional unit (subject, object, prepositional complement, adjectival complement, noun modifier, ...). Example:
Constituents can have different syntactic functions in different sentences. Examples:
- That big furry cat is sleeping --- That big furry cat is the subject of the sentence.
- (How do we know? With syntactic tests. For instance, if we change the number of the subject NP, the verb also changes (agreement): Those big furry cats are sleeping.)
- I saw that big furry cat (object).
- Bruna got mad at that big furry cat yesterday (prepositional complement).
Syntactic tests for constituency:
- "Movement" / alternative ordering.
- Topicalization or fronting: constituent appears at the beginning, separated with a comma (or prosodical equivalent, when speaking). Examples:
- She ate spaghetti with meatballs / Spaghetti with meatballs, she ate.
- She ate spaghetti with chopsticks / *Spaghetti with chopsticks, she ate. In this case, the test does not work because spaghetti with chopsticks is not a constituent (with chopsticks modifies the verb, not the noun).
- Clefting: re-build the sentence beginning with It is / it was followed by the constituent and a relative pronoun. Examples:
- It was spaghetti with meatballs that she ate.
- *It was spaghetti with chopsticks that she ate. Again, the test fails because spaghetti with chopsticks is not a constituent.
- It is that big furry cat who is sleeping.
- By pronoun, proper noun, or other single-word constituent. Examples:
- That big furry cat is sleeping / Lola is sleeping / She is sleeping.
- Bruna went to the fair / Bruna went there.
- By interrogative pronoun (aka WH-word) in partial questions (note that this test involves both rearrangement and substitution). Examples:
- That big furry cat is sleeping / Who is sleeping?
- Bruna went to the fair / Where did Bruna go?
- When a constituent is substitued by a WH-word in a partial question, the constituent is the natural answer to the partial question:
- Who is sleeping? Bruna.
- Where did Bruna go? To the fair.
- By nothing (so, better name for this test: omission). Watch out! It only works for constituents that are syntactically optional (that is, adjuncts rather than complements). Use with care. Examples:
- She ate spaghetti with chopsticks / She ate spaghetti.
- That big furry cat is sleeping / *Is sleeping. Note: Even if that big furry cat is a constituent, the test fails because subjects are compulsory. So, you should always apply more than one test to double-check conclusions.
Note: Asterisks signal ungrammatical constructions.