It has been an issue over the years that the Staff have not disregarded. Currently, pressing Shift + 3 when using the chatbox causes the game to crash as well, which is something I'd like to see get fixed.
However, I'd just like to clarify the Spanish users within FH do not go unnoticed.
I have a feeling that updating the game to enable the use of letters such as ñ and é requires the source code, which we di not have. If we were able to make such an update I have a feeling it would have been delivered quite the while ago to benefit those who speak other languages and use the letters.