It's learning languages by employing "thinking method" where you learn new language using English, mostly, as a basis. In the case of some languages, like Spanish, using the knowledge of common Latin roots. And thinking method itself focuses on learning the rules rather than memorizing individual words. Here[1] the author explains his method in details, in a guidebook for writers of new courses.

[1] https://www.languagetransfer.org/guidebook