CONSTITUENCY

Objectives:

• Understand the definition of constituent.

• Explore constituency tests including: standing alone, replacement and displacement.

• Start looking at representing these structures in tree format.

Constituents

Definition A constituent is an identifiable subpart of a sentence. It can either be a single word or a group of words that functions as a unit. Most constituents are called phrases. (We'll develop a better definition of “phrase” later.)

Comment In unit 3, looking at evidence from the formation of yes/no questions, we saw that rules like Subject/Auxiliary Inversion make reference to the internal structure of sentences. Constituents are these internal structures. In this unit, we look at how we identify these structures.

Discussion As a first step, we can observe that constituents typically correspond to strings of words that are bound together in terms of semantics. The relevant notion here is vague but hopefully intuitive: modification. If one word modifies the meaning of another, they will be linked together in a constituent. Consider the string the very big can of tuna. Look at the words very and big; notice how there is a close relationship between these. Very modifies big; it tells you how big the can is. Compare this to the relationship between very and can: very does not tell you how can something is! This means that there is a constituent consisting of very and big, but excluding can.