Hello! I've recently picked up learning Spanish because I work with a ton of dudes from Mexico. How much can I reasonably expect to learn from this app? I looked at their "curriculum" and it seems pretty short compared to what I think I'll need. What are some resources beyond "talk to your coworkers", that will put me on the right track?
Duolingo is a service as a software substitute owned by Google. It's designed in the same way Tinder is: to drip feed you content so that you buy their subscription model and log in each and every day.
Even if Duolingo somehow cracked the linguistic code and was the best language teaching software ever created, the fact that it uses a predatory business model of non-ownership and shallow gamification disqualifies it.
In other words, you should be able to take control of your language learning. Use textbooks, native speakers, movies, songs, personal writing etc. If duolingo went belly up and google shut it down, what would one be able to do? Invest in a personal anki deck or journal and find some textbooks online.
Since you have prior experience, I'd recommend "Gramática básica del estudiante de español" (2005) published by difusion. Its entirely in spanish but it has the best visual and textual explanations of introductory spanish grammar (though it is the spanish spoken in spain dialect called castellano) in my opinion.
I'll check this out when I'm a bit more fluent. I can string together some really basic sentences at the moment, and that's about it.