This reminds me of Venezuelan’s use of `vaina` (literally a husk), an all-purpose catch word that I’ve seen used to supplant other words/concepts that you don’t have at the tip of your tongue. In my native Spain I see people use `historia` (history).

It’s not a substitute of shit, thing, and stuff, since it can be used alongside these words and you can bring the `vaina` to the `vaina`.

Maybe the weirdness of `jawn` is it's not a word on its own therefore it cannot cause confusion?

Non-Philly, non-US, non-native English speaker here, so please excuse me if I’m not getting the gist of the article.