I am a college student who has been fascinated with languages for several years. I've studied some Latin, some Spanish, and some Mandarin, but mainly German. I have ambitions to learn several languages, but German and Mandarin are the most important ones to me.
I think anyone, not just children, can learn a language, and I don't think it has to take years. With the right study, teaching, and attitude, I think fluency is just a matter of work.