> Perl – While Perl's keywords and function names are generally in English, it allows modification of its parser to modify the input language, such as in Damian Conway's Lingua::Romana::Perligata module, which allows programs to be written in Latin or his Lingua::tlhInganHol::yIghun Perl language in Klingon. They do not just change the keywords but also the grammar to match the language.
That's impressive