Ambiguity in the English Language

An ambiguous statement in English followed by a question with a linguistic analysis.

STATEMENT: Security spotted a man with binoculars last week.

QUESTION: Did security use binoculars to find the man?

The analysis of the sentence divides the words into four phrases, listed in (1). The category of the phrase is determined by the syntactic category of the head. For each phrase in (1), the head is underlined and the syntactic category of the phrase is given in parenthesis.

(1)    Phrases in Security spotted a man with binoculars last week and category labels

1. Last week , (NP-Noun Phrase),  adjunct – time category
2. A man with binoculars , (NP), complement
3. spotted a man with binoculars,  (VP-Verb Phrase)
4.  Security (NP), complement

Each of the proposed phrases in (1), passes at least two constituency tests, shown in (2). Evidence that (1a), last week is an adjunct, is shown in (2e), (2f), (2g), and (2h) because adjuncts are compatible with any verb, and therefore not licensed by the verb, spotted. Adjuncts cannot be replaced with a pronoun, as shown in (2h). A man with binoculars, is a phrase comes from the movement test in (2i) and the question test in (2j). (2i) shows that a man with binoculars can be moved to the front of the sentence. The question test in (2j) shows that it is possible to ask a question that is answered with the phrase:  A man with binoculars. The tests in (2k) and (2l) provide evidence that spotted a man with binoculars last week, is a constituent. (2k) shows that this group of words can be represented by a single word, did. Given the right context, Security did, can mean the same thing as the whole sentence Security spotted a man with binoculars last week. (2l) shows that spotted a man with binoculars can be coordinated with another verb phrase of identical structure. The constituency tests in (2m) and (2n) provide evidence that the word, Security, functions as a phrase. (2m) replaces Security with a nominative pronoun and (2n) applies the question test.

(2) Constituency tests, evidence for the phrases in (1)

1. Compatible with any verb: Security interviewed a man with binoculars, last week.
2. Compatible with any verb: Security looked for a man with binoculars, last week.
3. Compatible with any verb: Security traded with a man with binoculars, last week.
4. Substitution: *Security spotted a man with binoculars, it.
5. Movement: A man with binoculars, security spotted last week.
6. Question: Who did security spot last week? A: A man with binoculars.
7. Substitution: Security did.
8. Coordination: Security spotted a man with binoculars and found a camera with batteries last week.
9. Substitution: It/They spotted a man with binoculars.
10. Question: Who spotted a man with binoculars? A: Security

The NP, Security, functions as the subject of the sentence, and the VP, spotted a man with binoculars last week as the predicate with one direct object (monotransitive). Evidence that Security is the subject is provided in (3).

(3)  Evidence that Security functions as the subject.

1. Auxiliary inversion: Did security spot a man with binoculars last week?
2. Security can be replaced with a nominative pronoun: They spotted a man with binoculars last week?
3. Security comes before the verb spotted.

The entire NP a man with binoculars is composed of the direct object of the verb spotted.  One property of typical objects is that they can be the subject of a passive sentence. This is true for a man with binoculars. In the passive sentence, A man with binoculars was spotted by security last week, the underlined NP, becomes the subject as evidenced by its agreement with the verb and its position in the sentence.

The relation between phrases is indicated by the tree diagram in (4).

(4) Tree structure of Security spotted a man with binoculars last week.

Whether or not the sentence Security spotted a man with binoculars last week indicates that security used binoculars to find the man depends on the syntactic structure of the sentence.

According to the structure in (4), Security spotted a man with binoculars last week indicates that security did not necessarily use binoculars to find a man. The structure in (4) indicates that the man had binoculars when he was spotted by security. In other words, with binoculars modifies a man.

It is possible for this sentence to denote that security used binoculars to find the man, but this would require that the prepositional phrase (PP), with binoculars, is attached directly to the VP, as indicated in the alternative tree structure in (5).

(5) Alternative tree structure of Security spotted a man with binoculars last week, in which with binoculars, (PP), is not a constituent.