Learning Mandarin, Japanese, and Russian Through Hindi

I recently discovered several resources for learning foreign languages through Hindi, which I found intriguing. Some of these resources are decades old, others are from the Internet age.

Mandarin: https://avtans.com/2020/07/04/learning-chinese-through-hindi/

Japanese: https://www.nhk.or.jp/lesson/hindi/

Russian 1: https://ia801603.us.archive.org/13/items/in.ernet.dli.2015.482818/2015.482818.Roosii-Praambhik.pdf

Russian 2: https://ia801602.us.archive.org/15/items/in.ernet.dli.2015.482819/2015.482819.Roosii-Praambhik.pdf