While it is true 0Ls don't know the language because they haven't prepared, when I wanted to learn Spanish, I moved to Spain for a year. I didn't pick up the language from "Spanish for Dummies." Likewise, law school is complete and total immersion. You will learn the language there, by reading cases and listening to professors. It is a system that has proven to be consistent. Don't freak out now. If you want to read a book about how to pass your first year, go for it, but it isn't necessary, and thousands of students have been successful in law school without it.