Ou se trouve la bibliotheque?

That's French for "Where is the library?"

Congratulations, you now know how to read a certain sentence in French. But you probably don't know how to say it. How is that possible? Well, you've only been exposed to it in writing, not speech. Repeat that many times for many sentences and words and you are literate in French but unable to speak it.

The answer to your question is the same, but in reverse - you are exposed to the language verbally but never learn to read or write it.