HTTP_Accept_language would be the normal setting.

Unfortunately, the error you are getting is from a generally used function, so the calling sequence is probably what is wrong. For these cases we need preferably a stack trace of the error. That may be possible to configure in your PHP. If not that then as much detail as to what was happening as possible.

I sent a message to my hosting provider to see if they can assist with the stack trace.

In the meantime, I will select only the HTTP_Accept_language and make sure I add AMERICA before making any text /options changes.

Great, we finally got a clue to what this is related! Probably still quite unique to your server as we neither heard nor encountered this anywhere before.