Phrase books are written for people who can't speak the language, so should you buy one? Some people who are learning a new language will buy them, but once you learn to form your own sentences the phrase book gets used less and less. Still, they are useful learning tools. A phrase book can form a fascinating puzzle by itself. You can learn a lot about a language by looking at how they put their sentences together. For instance, look at how words are arranged in a question compared to a regular statement. These kinds of mental games can give you a jump on learning how your language is put together. As you learn more about the language, you'll also find that phrase books are a good way to learn idiomatic expressions that will mark you as a competent speaker.