How is the word ‹only› analyzed in English? It seems unusually flexible.
Consider the following few sentences, each of which use the word ‹only›.
- Only students read yellow books.
- Students are the only readers of yellow books.
- Students read only yellow books.
- Students only read yellow books.
Sentences (1) and (2) mean the same thing as do (3) and (4). Only appears to function as a determiner phrase in (1) and (3), as an adjective in (2), and as an adverb of some sort in (4). (4) is a bit odd since ‹only› can be interpreted as modifying just the verb rather than the whole predicate in other contexts.
- Students only read yellow books; they don't write them.
- *Students read only yellow books; they don't write them.