The most challenging theoretical problem in linguistics is that of discoveringthe principles of universal grammar that interweave with the rules of particulargrammars to provide explanations for phenomena that appear arbitrary andchaotic.

In practice, the linguist is always involved in the study of both universal andparticular grammar.

there has been a tendency in popular discussion to confuse “deep structure”with “generative grammar” or with “universal grammar.” And a number of pro-fessional linguists have repeatedly confused what I refer to here as “the creativeaspect of language use” with the recursive property of generative grammars, avery different matter.