The Grand Master Plan Is the Name for Your Giant Page of Sound Changes

The grand master plan is the name for your giant page of sound changes to explain the change from in this case latin to britainic. Even though latin did have anything like a schle neither did proto-keltic it's a special thing that Welsh did on its own. The combination lt medially became sah hmm so that's interesting and that just plain old ordinary double l became a sah okay yeah um also i um as did as did the combination sl which makes a lot more sense to me  and maybe it's sort of the ell uh losing sonarancy because of the t or somethingYeah we shouldn't obsess over one sound change anyway