Translation of Lässigkeit

I try to learn English as much as possible so that I can travel next year to the United States. I would agree to your proposal but I also need to find good teachers. My goal is quality and speed.
Thank you for your answer. Your correction in Russian has helped me. I'm glad to have found a Russian Vocabulix friend with Russian as the mother tongue. I will help you in Spanish, OK?
I have already written some vocabulary lists on paper and typed in some of them here at Vocabulix. The automatic system here works better than flashcards on paper. Too bad there is no software.