Who invented the language Ijyji?

There is no known language called "Ijyji". It's possible you've misheard or misspelled the name of a language.

Could you please double-check the spelling or provide more context?

For example:

* Did you hear this language name in a movie, book, or game?

* Is there a specific region or culture associated with this language?

* Do you have any other information about the language?

With more details, I might be able to help you find the correct language name or identify its origins.