Questions: Syntactic Structure

Question 1

A linguist applies the substitution test to 'the old red barn' and finds it can be replaced by 'it.' What does this demonstrate?

• A. The phrase is semantically vague
• B. The words form a constituent — a unit that behaves as a single element in the syntax
• C. The phrase is the grammatical subject of the sentence
• D. The phrase contains a word-order error

Answer: (B)

The substitution test is a constituency test: if a group of words can be replaced by a single word (a pronoun substituting for a noun phrase), that group forms a constituent. This confirms 'the old red barn' is a noun phrase (NP) — a single hierarchical unit, not just adjacent words. Whether it is the subject is a separate question.

Question 2

The sentence 'Visiting relatives can be boring' is structurally ambiguous because it has two different word orders.

• T. True
• F. False

Answer: False

Structural ambiguity does not come from different word orders — it comes from one word order mapping onto two different syntactic structures (tree diagrams). Both readings of this sentence ('visiting relatives is boring' vs. 'relatives who visit can be boring') use the identical word sequence. The ambiguity arises because the same string of words can be parsed into two different hierarchical structures.

Question 3

Why do syntacticians draw tree diagrams rather than just listing the words of a sentence in sequence?

Model answer: Tree diagrams represent the hierarchical constituent structure of sentences, which cannot be captured by linear sequence alone. Sentences with the same word order can have different structures (structural ambiguity), and the grammar operates on structural relations — such as which phrases dominate or c-command others — that only the tree makes visible.

Movement rules, agreement, and ambiguity all depend on structural relations that a flat list of words does not convey. The tree represents which words form units, how those units are nested, and what grammatical relationships hold between them — the tacit knowledge that allows native speakers to recognize grammaticality and detect ambiguity.