Thanks for that last piece of information - I'm looking for concrete examples of where translation boosted sales and this fits the bill quite well. Have you localized for any other markets?
I have not localized the app itself. I feel like that is a lot of work for one person to maintain.
However, I have localized the App Store title, description, and keywords to as many markets as possible. I use Google Translate and my best judgement. Mostly, I just translate the word "piano" into different languages, to improve search. See my German page: http://itunes.apple.com/de/app/tiny-piano/id477014214
This has had a positive impact on sales in Germany, Japan, and Korea.
However, I have localized the App Store title, description, and keywords to as many markets as possible. I use Google Translate and my best judgement. Mostly, I just translate the word "piano" into different languages, to improve search. See my German page: http://itunes.apple.com/de/app/tiny-piano/id477014214
This has had a positive impact on sales in Germany, Japan, and Korea.