[summarity]

For sure, some common ground is needed. Madrigal's is a famous example of LT that almost exclusively focuses on transfer itself, because English and Spanish are reasonably similar.

LT's method goes a bit further though, hence why there are courses on Arabic, Swahili and (upcoming) Japanese. Chinese might be even further removed, but the LT courses are about learning to _think_ about how the language works, and the format of the course (teacher + median student + you) goes a long way to encourage this. Beyond Madrigal's "look how similar these words are".