DC native here too - this may just reflect my age but it seems like jawnks was relatively short lived in the late 80s/early 90s (at least I haven’t heard it sin

DC native here too - this may just reflect my age but it seems like jawnks was relatively short lived in the late 80s/early 90s (at least I haven’t heard it since then), ie a slang trend (not unlike the Greaseman-coined “dische” of the same era) rather than a long-lived linguistic change as it sounds like “jawn” is