Chomsky’s famous demonstration of the difference between
grammatical and well-formed was first published in 1957, and hasn’t yet
been replaced by a better one. Sentences (1) and (2) are equally
nonsensical, but any speaker of English will recognize that only the former
is grammatical.
1. Colorless green ideas sleep furiously.
2. Furiously sleep ideas green colorless.(Chomsky 1957)“*Furiously sleep ideas green colorless” is not grammatical for any
speaker of English, descriptivist or prescriptivist. No child growing up in
an English-speaking community would produce this sentence, just as you
never have to remind a child about other points of language-internal, rule-
governed grammaticality. When is the last time you heard somebody say
to a child something like: “Susie! Stop putting your articles after your
nouns!”
The concept of grammaticality might seem to be vague, because the
methodology is so very simple: a person is asked if a given sentence suits
their personal sense of well-formedness. A set of four sentences will help
demonstrate how this works:
1. Sam put a red scarf on the dog.
2. George took the dog.
3. Linda asked what Sam put the red scarf on.
4. *George took the dog that Linda asked what Sam put a red
scarf on.The first three sentences are grammatical (they sound well-formed, as
something you might say or hear said) for native speakers of English. The
third one will make most people stop and think, but it can be unraveled.
The last one cannot.
This process is used extensively by theoretical syntacticians, a field in
which linguists are not interested in variation or change in language. When
theoretical syntacticians come across native speakers who disagree on the
grammaticality of a given utterance (which will happen quite often), they
may note that as “noise,” but otherwise abstract away from it.