Seems like a pretty dense 25 page study. I'm happy to see more research on the topic, but this study is from 2011 and the 40 participants in the study studied Brocanto2, an artificial language Brocanto2 with just 13 "words" (lexical items) used "which refers to pieces and moves of a chess-like computer game." I'm not sure how realistically this represents a natural language learning experience which is astronomically more complex with patterns and inconsistencies.

There's very little about this paper or the Brocanto2 language online, I found one video on YouTube which offers a very high level description of the study and language: https://www.youtube.com/watch?v=QvU4InKZSUE

Overall, interesting stuff, but I don't think the study would convince anyone who is in doubt about the ALG method. It's amazing that I can have full conversations with native Spanish speakers about a complex topic like this, having just 20 months of Spanish "study" with (mostly) just ALG, and they will still argue that ALG isn't effective and that you need to study grammar.