Hi! I really loved this article, but have to caution against your interpretation that this work proved anything about language learning.
The use of the word "prove" really bothers me because there is a common misconception that science "proves" facts, when in fact science cannot prove anything- it can only provide supporting evidence, not-supporting evidence, and it can disprove information.
I am not at all refuting any of the points that you make in this article, but it especially bothers me when people writing about psychology-related topics use this word because there are so many articles in popular news media and otherwise that use "prove" incorrectly, or which indicate that data from a correlational study implies a causal relationship. I believe that these kinds of statements contribute to public misunderstanding of science.
Again- nothing against you, this topic or generally what you're writing about, just wanted to put this out there.