This is a free online textbook from the University of North Carolina. Each chapter has video, transcript, vocabulary, notes for grammar, vocabulary and culture, as well as some sentence patterns an... Read more.

learnnc.org

I've taken some book summaries of interesting non-fiction books, rewritten them into simple English and had them translated into Chinese. This way, the vocabulary and grammar will be easier to unde... Read more.

alllanguageresources.com

DigMandarin offer several interesting resources for free. The blog is a mix of directly useful resources, such as vocabulary for certain situations, and information/inspiration on learning Mandarin... Read more.

digmandarin.com

Finally, Duolingo added a En->ZH course. As Duolingo is the most popular gamification learning app, the learning experience is relatively streamlined and tested. The monetarization aspect leads to ... Read more.

en.duolingo.com