[rendall]

Interesting! It seems quite similar to the English-language Ubbi Dubbi, but for different purposes.

https://en.m.wikipedia.org/wiki/Ubbi_dubbi

Verlan seems quite similar to Pig Latin, come to think

[janci]

This also exists in slav languages - as a child secret speech. It is easier to understand than to say (both pronounce and construct the deformed word)