osTicket doesn't currently support multiple languages, though we'll be adding this feature in the future.
In the mean time, if you want to create your onw trnaslations, you're welcome to.
Most likely your problem is due to the fact that you're trying to use a character that isn't supported by the current character set that's defined, either in the database, or the pages you're serving, or the email parser. There are a number of places you'll need to change these.
I suggest you search the forums for 'utf8' and you'll get a number of results from others who've had similar issues, including infromation on hwo they fixed it.
