A couple years ago I saw a lecture by Luis von Ahn of Doulingo. He started the project not interested in education rather crowd sourcing but after a year he had

A couple years ago I saw a lecture by Luis von Ahn of Doulingo. He started the project not interested in education rather crowd sourcing but after a year he had 23 employees working on the education part and 2 working on the crowd sourcing of translations. He hired a couple esteemed leaders in acadamia on the subject of foreign language learning from prestigious universities as consultants. The question they asked the consultants was which part of speech should be taught to students learning a foreign language first? Do students learn faster if they learn verbs first or if they learn nouns? And, nobody could answer that so he got rid of the consultants and he and his engineers started to A/B different students using all the data they were gleaning. He says they answered those questions in a matter of weeks.