Usa of Relative Clauses in Conversation
By far the most interesting research on the use of relative clauses has been the work of Fox and Thompson (1990), who show that in American English conversation there are clearly preferred patterns of use according to the following criteria: (1) the syntactic roles of the head noun and the relative pronoun , (2) the definiteness and specificity (or identifiability) of the referent,(3) the animacy or humanness of the referent, and (4) the discourse function of the relative clause—that is, whether it functions to give background. Or new information.