I'm sure this comes up a lot but I experienced an accidental language switch just now, and wow - it is a pain to reverse. Switching between the two to practice both trees must be a royal pain.
In my case, I had been interested in seeing what the reverse Spanish tree looked like. I couldn't work out how to do it on the web browser but happened across it on my phone app. Whoops. The phone app, as far as I can tell, doesn't allow you to change back. I came on my laptop, still couldn't figure it out, and eventually found the solution via google (it's easy to find searching "change language duolingo" if you need it).
In the end it was no disaster, but it makes me think that it would be a lot easier if they changed the format to allow both to be learned at once the same as any other language. (E.g. I have English - Spanish and English - Swedish, but to get to Spanish - English is a massive faff).
Just thought I'd add my voice on the matter.
I'm currently just learning one language, but will soon be doing two. I would like it to be easier to switch back and forth, because I'm going to be trying to practise both equally and it does seem unnecessarily tricky.
Within the app, you have to click on add a language, then scroll down to the language you want to learn from (in your case, back to English) in order to switch back. It's a little counterintuitive when you've not done it before, but it can be done.
Ah thank you very much. Would be nice if it were made more intuitive, but that will do for now. Gracias!
There is a userscript to allow easy switching on the web. Nothing on the app unfortunately.
I'm doing Turkish and Polish from English, English from Turkish, and English from Arabic. At first, it was difficult doing the switching, but after a while it got easier. My biggest problem is switching from the English from Arabic tree because it take me a while to read Arabic. My Android phone makes switching back easy because I can read the names of the languages easily. At first, I would go to the phone to change languages, just to save a bit of time. Now, I'm fine on the computer as well. Clearly, my reading has improved! While I wish that I had a list of my languages to automatically change between languages, I am also learning from the switching. It's not such a big problem. There are lots of much more important things Duolingo could be working on.