Constituency Used in Grammar

An Easy Way to Analyze Sentences

Wooden Letters With Focus On 'ABC'
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In English grammar, a constituency is a relation between a linguistic unit (i.e., a constituent) and the larger unit that it is a part of. For instance, all the words and phrases that make up a clause are said to be constituents of that clause. A constituent can be a  morphemewordphrase, or clause. When you are analyzing a sentence, for example, to find the subject or predicate or identify the different parts of speech, you are parsing the sentence into its constituents. It actually sounds more complicated than it is.

One method of analyzing sentences, commonly known as immediate constituent analysis (or IC analysis), was introduced by American linguist Leonard Bloomfield ("Language," 1933). Though originally associated with structural linguistics, IC analysis continues to be used (in various forms) by many contemporary grammarians. The constituency is traditionally represented by bracketing or tree structures.

David Crystal explained,

"[A] sentence can be analysed into a series of constituents, such as subject + predicate, or NP [noun phrase] + VP [verb phrase], etc. These units thus produced can, in turn, be analysed into further constituents (e.g. a noun phrase might consist of a determiner and a noun), and this constituent analysis process can be continued until no further subdivisions are possible. The major divisions that can be made within a construction, at any level, are known as the immediate constituents (ICs) of that construction. The irreducible elements resulting from such an analysis are known as the ultimate constituents (UCs) of that construction." ("A Dictionary of Linguistics and Phonetics," 6th ed. Blackwell, 2008)

Examples of Immediate Constituent Analysis

Author Alex Klinge further illustrates the technique of breaking down sentences with an example:

"The sentence The boy will sing contains four word forms the, boy, will and sing. The four word forms are constituents of the sentence. However, it should be clear that the four constituents are not equally ranked. The seems to be related with boy in a more immediate way than with sing, and will seems to be more immediately related with sing than with the. We can show this by arranging them together as groups inside square brackets [the boy] [will sing]. We can now say that from this perspective the sentence The boy will sing has two constituents, two groups. These two larger chunks are immediate constituents of the sentence." ("Mastering English." Walter de Gruyter, 1998)

In the next example, the "Analyzing English Grammar" authors analyze how the constituents are chosen, what makes some pieces part of one immediate constituent as opposed to another, illustrating with the sentence "Edward grows tomatoes as large as grapefruit." 

"​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:
(19) A noun phrase subject: Edward
A verb phrase predicate: grows tomatoes as large as grapefruit
(20) A main verb phrase: grows
A second noun phrase: tomatoes as large as grapefruit"​ (Thomas P. Klammer, Muriel R. Schulz, and Angela Della Volpe, 4th ed. Pearson, 2004)

When you apply the substitution test to your chosen constituents, you are using the technique of "expansion."