Immediate constituent analysis (IC)


Immediate constituent analysis : A method in Grammatical analysis 

In linguistics, immediate constituent analysis or IC analysis is a method of sentence analysis that was first mentioned by Leonard Bloomfield, and developed further by Rulon Wells. The process reached a full blown strategy for analyzing sentence structure in the early works of Noam Chomsky.The practice is now widespread. Most tree structures employed to represent the syntactic structure of sentences are products of some form of IC-analysis. The process and result of IC-analysis can, however, vary greatly based upon whether one chooses the constituency relation of phrase structure grammars (= constituency grammars) or the dependency relation of dependency grammars as the underlying principle that organizes constituents into hierarchical structures.

binary principle

IC-analysis in phrase structure grammars

Given a phrase structure grammar (= constituency grammar), IC-analysis divides up a sentence into major parts or immediate constituents, and these constituents are in turn divided into further immediate constituents. The process continues until irreducible constituents are reached, i.e., until each constituent consists of only a word or a meaningful part of a word. The end result of IC-analysis is often presented in a visual diagrammatic form that reveals the hierarchical immediate constituent structure of the sentence at hand. These diagrams are usually trees. For example:

tree structure 1

This tree illustrates the manner in which the entire sentence is divided first into the two immediate constituents this tree and illustrates IC-analysis according to the constituency relation; these two constituents are further divided into the immediate constituents this and tree, and illustrates IC-analysis and according to the constituency relation; and so on.

An important aspect of IC-analysis in phrase structure grammars is that each individual word is a constituent by definition. The process of IC-analysis always ends when the smallest constituents are reached, which are often words (although the analysis can also be extended into the words to acknowledge the manner in which words are structured). The process is, however, much different in dependency grammars, since many individual words do not end up as constituents in dependency grammars.

IC definitions


1 . Un gentlemanly
This will be broken down into un-gentlemanly —-> un- gentleman-ly —-> un-gentle-man-ly—–> un-gentl-e-man-ly
un + { [(gentle- + le ) + man ] + -ly

As we break the word we obtain at any level only two immediate constituents (IC)s, one of which is the stem of any given word.

IC main requirement


A given word/node plus all the words/nodes that that word/node dominates

This definition is neutral with respect to the dependency vs. constituency distinction. It allows one to compare the IC-analyses across the two types of structure. A constituent is always a complete tree or a complete subtree of a tree, regardless of whether the tree at hand is a constituency or a dependency tree.

Morphology in IC

Constituency tests

The IC-analysis for a given sentence is arrived at usually by way of constituency tests. Constituency tests (e.g. topicalization, clefting, pseudoclefting, pro-form substitution, answer ellipsis, passivization, omission, coordination, etc.) identify the constituents, large and small, of English sentences. Two illustrations of the manner in which constituency tests deliver clues about constituent structure and thus about the correct IC-analysis of a given sentence are now given. Consider the phrase The girl in the following trees:

tree diagram 2

The acronym BPS stands for “bare phrase structure”, which is an indication that the words are used as the node labels in the tree. Again, focusing on the phrase The girl, the tests unanimously confirm that it is a constituent as both trees show:

…the girl is happy – Topicalization (invalid test because test constituent is already at front of sentence)

It is the girl who is happy. – Clefting

(The one)Who is happy is the girl. – Pseudoclefting

She is happy. – Pro-form substitution

Who is happy? -The girl. – Answer ellipsis

Based on these results, one can safely assume that the noun phrase The girl in the example sentence is a constituent and should therefore be shown as one in the corresponding IC-representation, which it is in both trees. Consider next what these tests tell us about the verb string is happy:

*…is happy, the girl. – Topicalization

*It is is happy that the girl. – Clefting

*What the girl is is happy. – Pseudoclefting

*The girl so/that/did that. – Pro-form substitution

What is the girl? -*Is happy. – Answer ellipsis

The star * indicates that the sentence is bad (i.e. it is not acceptable English). Based on data like these, one might conclude that the finite verb string is happy in the example sentence is not a constituent and should therefore not be shown as a constituent in the corresponding IC-representation. Hence this result supports the IC-analysis in the dependency tree over the one in the constituency tree, since the dependency tree does not view is happy as a constituent.

In summary:

Immediate constituent analysis is a form of linguistic review that breaks down longer phrases or sentences into their constituent parts, usually into single words. This kind of analysis is sometimes abbreviated as IC analysis, and gets used extensively by a wide range of language experts. This kind of exploration of language has applications for both societal or traditional linguistics, and natural language processing in technology fields.

For those who use this kind of analysis to examine text or speech, immediate constituent analysis often requires separating parts of a sentence or phrase into groups of words with semantical synergy or related meaning. For example, the sentence, “the car is fast,” could be broken down into two groups of words: “the car” and “is fast.” In this case, the first group contains an article applied to a noun, and the second group contains a verb followed by a defining adjective.

Many kinds of immediate constituent analysis include multi-step processing. For the example above, the two groups of words could be split up further into individual words. Reviewers might consider how the article “the” applies to the word “car,” for instance, in specifying one particular car, and how the adjective “fast” describes the verb “is,” in this case, in a simple, rather than a comparative or superlative sense.


Akmajian, A. and F. Heny. 1980. An introduction to the principle of transformational syntax. Cambridge, MA: The MIT Press.

Ágel, V., L. Eichinger, H.-W. Eroms, P. Hellwig, H. Heringer, and H. Lobin (eds.) 2003/6. Dependency and valency: An international handbook of contemporary research. Berlin: Walter de Gruyter.

Bloomfield, Leonard. 1933. Language. New York: Henry Holt ISBN 0-226-06067-5, ISBN 90-272-1892-7


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