Textbooks alone won't make you fluent. The speaker learned English from watching Friends and talking to native speakers, not from grammar drills. Real exposure to how people actually speak matters more than memorized vocabulary.
I don't think I've ever used a single word from a textbook. To learn a language, you have to have exposure. You need to be in the environment, in the surroundings. Like, everything that came to me now, the way I'm speaking English, came from experience and interacting with people. Nothing I've ever learned came out of a textbook. In college, when I was studying in Korea, I was helping Koreans speak English better. I made them watch Friends. It's kind of outdated, but still the phrases are very natural, and a lot of Koreans these days use the series, any series to be honest, to learn the language. Textbook can only do so much, but it's so different than interacting with the people who speak the language.
