Chaucer died (25/10/1400)

https://en.wikipedia.org/wiki/Geoffrey_Chaucer
(French chaucier, once thought to mean 'shoemaker', but now known to mean a maker of hose or leggings) (Wiki)
But Geoffrey's immediate ancestors were vintners and merchants in Ipswich.
"The Reeve's Tale" is (saith Crystal) the first time regional dialect features are used for literary effect, and without any suggestion that they were inferior to the courtly speech of London.
Two young Cambridge students of Northern origin get revenge on a miller (Southern) who has been defrauding their college of corn.
The students have "na" where the miller (and the reeve telling the story) have "no".
Likewise Northern -s vs. Southern -th in 3rd person singular present (has/hath). Northern "ga", "fra"; Southern "go", "fro".