Grand Master Plan

Grand Master Plan is a jocular term orignally used by Andrew Smith to describe the historical phonology of Brithenig as the plan for how to turn Latin into a language similar to Welsh, with reference to master plan as a term for the hidden agenda of a cabal. Later used for the historical phonology of any bogolang, and then by extension for the historical phonology of any histlang, virtually becoming a conlangers' in-group synonym for historical phonology.