I thought of this myself and had a few ideas for current workarounds:
You could define an array to hold all the languages.
On runtime, you can select the array corresponding to the selected language.
Problem with this, you have to manually edit the array every time something changes and you have to recompile.
2. Outsourced Languagefiles (maybe a simple PHP Script?)
You can setup language files on your server and you get the strings per AJAX GET or POST Request.
Problem, you need to know how to script such stuff :)