Unfortunately there isn't any integrated internationalization features for the ticket system, so all of the changes would have to be tediously added to each of the templates.
If you severely need the system to be translated to your native language, I would suggest just going for it. Updates don't seem to happen all too often, and if you do need to update in the future, just simply keep track of all of the files you've added translations to and compare it with the files of the update.
If you're particularly code-savvy and don't mind a weekend project, it may be worth writing up a little regex-replacer to automatically search for words or sentences and replace them with a translation. Obviously this would still require you to manually go through each of the files and find the English words, but you would only need to run the program whenever you need to translate all of the files again.
Edit: Just realised your problem is that the language is American-English and not English. Is it really that big of a problem? At the most you'll only need to change a few words which shouldn't really be that difficult or tedious.