It is set at Dutch, don't ask me how because I don't know. Nothing on Google or the manual. Thanks!
Penguin, Google gave me this:
Change Localization TI-83
Its a .pdf file.
Basically it says this:
You can localize the TI-83 Plus or TI-83 Plus Silver Edition so that it will
display menus, prompts, functions, and error messages in a language
other than English.
Note: If you choose to reset All RAM or Arc Vars, the language is unaffected.
However, if you reset Apps or All Memory, the language App is deleted and the
language reverts to English.
I have a TI-84 Plus.