Change in content??
A couple of questions:
Is there any difference in content in Duo plus or is the primary difference the ability to practice offline?
Second, is there new content in the program? I reached level 25 in French and switched over to the reverse tree (french to english) where I am at level 14. I recently went back to french as I saw my proficiency level was dropping (from lack of use apparently - one apparently does not get "cross-credit" for working a reverse tree.)
It seems to me I am seeing new sentences - which I highly welcome.
However, is that true or have I simply forgotten them from my earlier work?
Duolingo Plus removes adverts and gives a limited amount of offline functionality.
Using reverse trees, you will encounter new vocabulary and sentences.