Yep, I understand what you’re saying about the free vs. pay courses. Last 2 yrs., the MOOC industry has been undergoing a radical transformation as it prioritizes on users who are willing to pay.
For learning languages, have you checked this site out?
They don’t provide the online classes themselves; they’re an aggregator (like kayak.com for travel) so they compile & point to other sites who have free classes. They list 48 language courses. I don’t know about the quality. Overall, they list over 1300 free courses; they know about free textbooks, free e-books & a whole bunch more free stuff listed on the right side of this page: [http://www.openculture.com/faq]
You mentioned Chinese; IDK if you want to learn Chinese, but here’s an online Coursera Chinese for Beginners course from U of Peking that starts tomorrow; I’ve used Coursera for about 10 yrs; they’re free as long as you don’t want a certificate or specialization. [https://www.coursera.org/learn/learn-chinese]
Hope this helps!