For people still having this problem:
Like these guys said earlier, you'll have to all that crap with it's software, if it's a cheap one.
If it's a branded one, there'll a language option.
If you have a cheap one, you'll have to download 'Bing Translator' or 'Google Translate', which have offline live translation option. That's what I'm using on my pop's Vitz.
Edit: The Bing Translator doesn't have offline Japanese available. If you have Windows Phone, hard luck, because google's isn't available. 