Extensive reading is not the only way to learn a language. Most language scholars would agree that language students still need to spend a lot of time practicing speaking, listening, writing, and so on in order to become advanced in the language. However, adding extensive reading to your private study can certainly do some great things for your language ability. Not only is extensive reading effective, but it can be a very enjoyable way to learn a new language. Give it a try and see what it will do for you!