The trick to competing with Duolingo is to _actually_ teach people new languages that they actually learn, rather than giving away the illusion that they are learning a new language on Duolingo.
At the end of the day, whether it's effective or not, Duolingo sells the feeling that you are learning a language to people. Winning a competition with Duolingo means doing better at making people feel like they are learning a language -- the strategy to win against Duolingo probably involves watering down the learning even more, to better sell the feeling.
A good way to think about it is look at some organization that wants to be effective at actually teaching its employees a new language, like the state department:
https://www.state.gov/foreign-service-institute/foreign-lang...
20 hours a week of intensive instruction.
Spanish 30 weeks Cantonese 88 weeks Turkish 44 weeks
This is what it actually takes.
Duolingo is for people that will never travel for more than a weekend once every other year, and its fine that its entertaining for them or their last minute crash course to feel less ignorant. Lately I've seen it used by people that want to feel closer to their roots.
But I don't think people actually engaging with other cultures and going abroad to do so are still using this. On the other hand, LLM's are really good at slang and colloquialisms, something neither Duolingo or an in person teacher will reveal to you.
I'm just very unsure whether it's possible to design an effective language learning program that is "engaging" in the way that Duolingo users want it. At the end of the day, you should feel engagement from using the language (and seeing yourself improve) and not from external gimmicks.
That said, I do think betting against Duolingo will pay off long term. But the put options are so expensive... probably better to just short the shares
I disagree that it's an illusion. People are learning a new language when using Duolingo, but 5-10 minutes/day means it will take a long time before they are proficient. Someone else linked to the state department website showing 550-690 hours of learning required on the English adjacent languages.