One of the more well-known examples, and one that made me double-take when I saw it - from PHP 3 onwards, when a pair of Israelis rewrote the parser, a common and confusing syntax error was "unexpected T_PAAMAYIM_NEKUDOTAYIM". Which is Hebrew for T_DOUBLE_COLON.

In PHP 5.4, they helped the situation somewhat by changing the error message to "unexpected '::' (T_PAAMAYIM_NEKUDOTAYIM)" - I suspect national pride was involved in their refusal to completely remove the internal token name from the error message.