Can I learn any language with these methods?
Basically you can. Our personal experience naturally only encompasses a small fraction of the thousands of cultures and languages on Earth. Yet language acquisition appears to be a universal human ability that works the same way in every culture and with all linguistic structures.
At the same time every language exhibits specific features and peculiarities. You will have to adapt your techniques to the target language just as you will have to adapt them to your situation and your individual needs.