Language Contact in Piers Plowman.
The instability of fourteenth-century diglossia in England is mirrored in PPl. Latin is recognized as the self-validating language of authority, yet an utterance in it can be grammatically false, with destabilizing implications for the text of which it is a part. Code switching, which involves alteration of an entire grammatical system, often undercuts the authoritative prestige of Latin, since the Latin passages are not systematically conditioned by speaker, topic, or interlocutor; are sometimes not semantically significant; or are presented by disreputable characters. Nominalism, expansion of a market economy, and the Lollard movement all contributed to the instability of the English social and linguistic situation. Gower, in Confessio Amantis, imputes authorship to himself but, significantly, does so in Latin that frames the vernacular; PPl implies that the traditional diglossic boundaries have begun to overlap.
Speculum 69 (1994): 359-85.
Machan, Tim William.