I work for a foreign language instruction services company. We mostly serve government and military, but we do accept private students. All of our linguists are extremely skeptical of apps like Duolingo. And before anyone replies something like "your company has a vested interest in propping up instructor-led language training", if apps like Duolingo actually worked, the government--especially the military--would sto…
Based on my experience of language learning, I agree with you.
> The OP take about having used Duolingo for almost 10 years. That seems absurd to me. I would hope they have mastered at least half a dozen languages with that kind of effort.
This completely glosses over the costs involved.