Self-paced, mastery-based, personalized learning can develop within students the intrinsic motivation required to become truly proficient with any knowledge of skill. I believe Duolingo is a great way to help kids learn to love language.
Learning new languages is so great for the developing brain, and French of course is the number one required language after English in Canada. We encourage students to dive deep into French, but they also love to dabble with their native tongue, and other languages that inspire them.