Who narrates the prologue, and what is its purpose?

The narrator of the Prologue might be Chaucer, but this is not to confuse him with Chaucer the author.  He explains, in fact, that he is only acting as the faithful reporter of what others have said, without adding or omitting anything; he must not then be blamed for what he reports.  "My wit is short, ye may well understand," the narrator says.  This persona, who almost becomes a character in himself, often professes a naivety that we often find in his ironic descriptions of the pilgrims.  Often that narrative voice presents information uncritically but ironically in that the author behind the narrative voice does the criticizing.