I agree. You have to use it.
People who are fluent in a language, but, don't use it....will lose it.
There's Pimsleur, which is a program that teaches through "sound"....just like you learned as a baby. Your parents spoke at you and you repeated. Pimsleur works on those same principles.
I think it is best that you actually "hear" the language. That it gets absorbed through your ears, as well as through your eyes (through reading).
Get the basics....and then go find a group who speak that language and be with them.