Recently, when I started to search for some english skills i've discovered the most difficult thing about learn english and every language, i guess: We have difficulty not just about get new vocabulary or memorize grammatical structures.. The hardest thing is transpose our own mater language line of reasoning and change our mind to absord the thought way that other people use to live and reason. 

It's not simply learning of new words, it's a real metanoia, and when we get that specific skill we can undertand better any people in yours more intimate ideas.