Constituent: Definition and Examples in Grammar

In English grammar, a constituent is a linguistic part of a larger sentence, phrase, or clause. For instance, all the words and phrases that make up a sentence are said to be constituents of that sentence. A constituent can be a morpheme, word, phrase, or clause. Sentence analysis identifies the subject or predicate or different parts of speech, a process known as parsing the sentence into its constituents. It actually sounds more complicated than it is.

Constituent Definition 

Every sentence (and every phrase and clause) has constituents. That is to say, every sentence is made up of parts of other things that work together to make the sentence meaningful.

For example, in the sentence: "My dog Aristotle bit the postal carrier on the ankle," the constituent parts are the subject, made up of a Noun Phrase ("my dog Aristotle"), and the predicate, a Verb Phrase ("bit the postal carrier on the ankle").

• A Noun Phrase (abbreviated NP) is made up of a noun and its modifiers. Modifiers that come before the noun include articles, possessive nouns, possessive pronouns, adjectives, or participles. Modifiers that come after include prepositional phrases, adjective clauses, and participle phrases.
• A Verb Phrase (VP) is made up of a verb and its dependents (objects, complements, and modifiers).

Each of the phrases in the sentence can be further broken down into its own constituents. The Subject NP includes the noun ("Aristotle") and a possessive pronoun and noun ("My dog") that modify Aristotle. The Verb Phrase includes the verb ("bit"), the NP "the postal carrier," and the prepositional phrase "on the ankle."

Immediate Constituent Analysis

One method of analyzing sentences, commonly known as immediate constituent analysis (or IC analysis), was introduced by the American linguist Leonard Bloomfield. As Bloomfield identified it, IC analysis involves breaking a sentence down into its parts and illustrating it with brackets or a tree diagram. Though originally associated with structural linguistics, IC analysis continues to be used (in various forms) by many contemporary grammarians. 

The purpose of Immediate Constituent Analysis is to understand the way sentences are structured, as well as discover the deep meaning of the intended sentence and perhaps how it might be better expressed.

In this diagram, the sentence "My dog Aristotle bit the postal carrier on the ankle" has been broken down (or "parsed") into its separate constituents. The sentence contains a subject and predicate, parsed as Noun Phrase and Verb Phrase: those two things are known as the Immediate Constituents of the sentence. Each IC is then further analyzed into its own constituent parts—the IC of the Verb Phrase includes another Verb Phrase ("bit the postal carrier") and a Prepositional Phrase ("on the ankle"). The contents of the IC—for example, the subject noun phrase includes determiner, noun, and modifier—are known as the ultimate constituents (UC) of that construction; they cannot be further broken down.

The sentence "The boy will sing," contains four word forms: an article (the), a noun (boy), a modal verb (will), and a verb (sing). Constituent analysis recognizes only two parts: the subject or noun phrase (the boy) and the predicate or verb phrase "will sing."

The Substitution Test

So far, the sentences have been fairly straightforward. In the sentence "Edward grows tomatoes as large as grapefruit," the constituent parts are the subject (that would be Edward) and the predicate ("grows tomatoes"); another constituent is the phrase "as large as grapefruit," a noun phrase that modifies the noun of the predicate. In constituent analysis, you're looking for the basic underlying structure.

The substitution test, or more properly "proform substitution," helps identify the underlying structure by replacing a text string in a sentence with a suitable definite pronoun. That allows you to determine whether the sentence constituents are broken down into the smallest salient pieces, words that can be replaced by a single part of speech. The sentence "My dog Aristotle bit the postal carrier on the ankle" could be reduced to "He bit (something)" and "something" is the object of the verb, so there are two main parts—noun and verb—and each of those is considered a constituent part of the sentence in the diagram.

To get to the bottom of Edward and his tomatoes, textbook authors Klammer, Schulz, and Volpe walk us through the logic by using the substitution test:

"​Edward, the subject, is a single noun and is, according to our definition, a noun phrase as well. The main verb grows stands alone without any auxiliaries and is the entire main verb phrase. Although tomatoes, by itself, could be a noun phrase, in identifying constituents of the sentence, we are looking for the largest sequence of words that can be replaced by a single part of speech: a noun, a verb, an adjective, or an adverb. Two facts suggest that tomatoes as large as grapefruit be considered as a single unit. First, in this sentence, the entire phrase can be replaced either by a single word tomatoes (or by a pronoun like something), yielding a complete sentence: Edward grows tomatoes or Edward grows something. Second, if you divide this structure, no single word can replace as large as grapefruit in this structure, while supplying similar information about the tomatoes. If, for example, you try to substitute a simple adjective like big for the phrase, you get *Edward grows tomatoes big. Thus, the complete sequence tomatoes as large as grapefruit is a noun phrase constituting part of the predicate, and we identify the sentence constituents as follows:

A noun phrase subject: Edward

A verb phrase predicate: grows tomatoes as large as grapefruit

A main verb phrase: grows

A second noun phrase: tomatoes as large as grapefruit."

Sources

• Bloomfield, Leonard. "Language," 2nd ed. Chicago: University of Chicago Press, 1984. 
• Crystal, David. "A Dictionary of Linguistics and Phonetics," 6th ed. Blackwell, 2008.
• Klammer, Thomas P., Muriel R. Schulz, and Angela Della Volpe. "Analyzing English Grammar," 4th ed. Pearson, 2004.
• Klinge, Alex. "Mastering English." Walter de Gruyter, 1998
• Leech, Geoffrey N., Benita Cruickshank, and Roz Ivanic. "An A-Z of English Grammar & Usage," 2nd ed. Longman, 2001.
• Miller, Philip H. "Clitics and Constituents in Phrase Structure Grammar." Garland, 1992
• "Oxford Dictionary of English Grammar." Oxford University Press, 1994