I understand what you mean. Having lived in a non-English speaking country for three years now I can understand a lot more than I can speak. I can get by with broken Tagalog, though. But it takes time, and I'd never be able to do something technical outside of my native language. Hats off to you!
Don't worry about people stealing your ideas. If your ideas are any good, you'll have to ram them down people's throats.