Constituency Tests

Constituency tests are diagnostic procedures that probe whether a string of words forms a syntactic constituent, providing empirical support for hierarchical phrase structure.

Definition

A constituency test is a syntactic operation, such as substitution, movement, or coordination, whose successful application to a string of words is taken as evidence that the string forms a single constituent.

Scope

This topic covers the standard diagnostics for constituency, including substitution by a pro-form, movement (clefting, topicalisation, fronting), coordination, fragment-answer, and ellipsis tests, together with their logic and limitations. It does not cover the schema of phrase structure itself or the rules that generate it, which are treated in sibling topics.

Core questions

• How can we tell whether a string of words is a constituent?
• What does it mean when a string can be replaced by a single pro-form?
• Why can constituents be moved, coordinated, or stand as fragment answers?
• Why do constituency tests sometimes give conflicting results?

Key concepts

• substitution test
• pro-form
• movement test
• coordination test
• fragment-answer test
• ellipsis test

Key theories

Substitution and pro-form replacement

The diagnostic that if a string can be replaced by a single pro-form such as 'it', 'do so', or 'there' while preserving grammaticality and meaning, it is a constituent of the relevant type.

Movement and coordination diagnostics

The diagnostics that only constituents can be displaced as a unit (clefting, topicalisation) or coordinated with a like unit, providing converging evidence for constituent boundaries.

History

Constituency diagnostics descend from the immediate-constituent analysis of American structuralism, which sought to segment sentences into nested units. Generative syntax retained and refined these tests as evidence for the hierarchical structures posited by phrase structure grammar. Modern textbooks such as Radford (2009), Carnie (2013), and Sportiche, Koopman and Stabler (2014) codify a standard battery of tests while cautioning about their fallibility.

Debates

Reliability of constituency tests

Whether constituency tests are decisive or merely suggestive, given that different tests can yield conflicting verdicts and that some apply only to particular categories.

Key figures

• Andrew Carnie
• Andrew Radford
• Dominique Sportiche
• Hilda Koopman

Seminal works

• carnie2013
• radford2009
• sportiche2014

Frequently asked questions

What is the simplest constituency test?

Substitution: if a string can be replaced by a single word such as a pronoun and the sentence remains grammatical, the string is likely a constituent. 'The tall man left' becomes 'He left', showing 'the tall man' is a constituent.

Why do tests sometimes disagree?

Tests can be sensitive to factors beyond constituency, such as information structure or category restrictions, so a string may pass one test and fail another. Linguists therefore rely on converging evidence from several tests.