I can't access the thesis either, but I believe it's "‘Picking Up’ a Second Language from Television: an autoethnographic L2 simulation of L1 French learning".

https://core.ac.uk/download/pdf/189928232.pdf

I don't know what the research is, but the best way I know to learn a language is to acquire a lot of data at the edge of your comprehension.

Basically, keep just listen to/read things in the target language, that you barely understand. Don't bother with grammar and rules, that's not how anyone thinks or speaks a language.

I'd love to see what's in OP's link, though.

Reposted with editable accessible link above.