If your Echofon UI language turns into Japanese after version 3.1, it because you set Japanese language priority higher than English. This happens if you've tried Emoji keyboard before.

To solve this issue:

1. Open Settings.app (Apple system wide preference application)
   
2. Go to General -> International
   
3. Select language to "English"
   
4. Do 1-3 again, and select language to your native language