Bilingual Learning of 3rd language
As a native English speaker and fluent in Spanish (majored and used to lived in Spain, just working through the course now to refresh some vocab) I am seeing an opportunity to learn a 3rd language by using the two parent languages. I am currently working on French, which I started in English, although it more closely resembles Spanish. After starting the Catalan course in Spanish, I think it would be highly beneficial to interact the 3 languages (EN, ES, FR) while learning the 3rd.
I think this would easily be done by allowing to change the language of the course by taking the sets completed in one language (EN) and applying them to the sets of the other language (ES) to in the course that is being completed (FR).
The point is not for him to review a second language while he obtains the third, in which case one could just do as you say, like I started the German tree in French mode to learn German and review French simultaneously. No, the object here is two look at a language from two different language-perspectives in order to gain a better understanding of the target language. What we do right now is like shooting an arrow with one eye open, we have no depth perception, because we only go from lang 1 to lang 2 and back again, there are subtleties lost on us. If we can open that second language-eye, we'll immediately understand what we are learning on a deeper level. Not to mention any training that incorporates more than two languages would be an absolute godsend for polyglots.
What do you suggest exactly? How would you train all three languages at the same time? How is the "second language eye" opened?
As we know that the OP is bilingual in both English and Spanish, I didn't suggest the French for Spanish speakers course as a method to review Spanish. Also, Duolingo is a beginners course, so it's not surprising at all that some subtleties are lost in translation.