Recently Duolingo sold for the first time shares publicly on the Exchange market. Since 2018 I have been studying Spanish with it. I had Spanish the last year of elementary school, in high school from the first year till third year VWO, and two years in my Business Economic Studies. It wasn’t a good match back then, but now with the Duolingo method it is easier.
I can recommend this app to everybody. I am also relearning French with this app. I had French in high school from second year till 4th year. It was a challenge back then, but I love this language and even had an assignment in this language. I wrote the blog 'Coding Emotions In Categories From A Survey Answer' about this assigment.
I can learn as many languages as I want at once in the paid version, but in the free version up till 5 I think. Papiamentu is not in it yet, but there are a lot of very exotic language I can take on.