Adding localization support

Hello,
I'm having problems with adding localization to my plugin, Sysinfo. The main idea is to have several files (locale-en, locale-pl, locale-zh, locale-de etc.) inside jar. Each locale would be in YAML format and work as a config file (i've seen stuff like config.yml and data.yml in some plugins' folders). The problem is i ran out of ideas how to make this. I have never been implementing locales, so they are a bit new to me. The source code: GitHub.