Thanks for the info, that's very interesting.

> The fact you don't know about it doesn't mean it doesn't exist.

I take your point.

Interestingly, growing up in the late 80s, we were briefly taught Zhuyin (https://en.wikipedia.org/wiki/Bopomofo), but not this. I don't believe my parents (both native Shanghainese) even know how to "spell" Shanghainese.

Ah, the lost art...