Languages don’t require a book to learn. They only require a community. Books help when you don’t have people around, but when you meet people who speak your language, make the most of the encounter. Introduce yourself, tell them how much you love their language, and see if they can help you advance.
Let me explain how I learn Somali in Minnesota. Realize that I don’t live close to a Somali community, that is, I don’t run into Somalis on a daily basis. I have to drive intentionally to where I know Somalis frequent.
Memorization lies at the foundation of my Somali work. I read some books and articles just to glean vocabulary—individual words and phrases. I put them into my Anki deck, and I go through my deck every day at about 5am. I do it at that time because the day gets too busy otherwise and I forget.