It's so strange to hear you and GP talking as if no one has ever learned a foreign language without moving to another country. The US military has been teaching translators for decades at the Defense Language Institute in California, and people learn languages to conversational fluency in university, albeit inefficiently. Duolingo is a game meant to be fun and collect subscription fees, not designed to teach any useful skill.
(GP here) There’s a big difference between techniques that could be feasible for an app (presumably used by people who want to study one hour or less per day) and techniques you can use with people who are dedicating their entire professional workday to language learning for weeks/months on end.
I guess my original comment could’ve been more specific, but I figured the context was implied.
> It's so strange to hear you and GP talking as if no one has ever learned a foreign language without moving to another country.
I speak three languages fluently (two prior to moving to said country; English, for example, is not my native tongue), so that's a weird assumption to make. With that said, I still think it's the most efficient way to learn a language, especially given how almost everyone's a nomad (especially in tech) these days.