Since I’ve transitioned in my work to being more interested in lexicography, I haven’t had time to do a significant amount of reading in Second Language Acquisition. But, I recently picked up The Neurobiology of Learning: Perspectives from Second Language Acquisition. I would highly recommend it to anyone with the responsibility of teaching languages, whether ancient or modern.
Some readers may find the neurobiology a bit dense, but it’s not too dense if you have read at least a little bit on the subject. I may be misjudging that since I did my undergraduate work in psychology, but even so, I think the structure of the chapters makes it possible for anyone to benefit from the book.
The chapters are generally structured with an introduction, a section on the neurobiology of a particular area, e.g. motivation, attention, etc., and then a section drawing applications from the neurobiology. I think the application sections are readable for anyone.
Some insights from the book were new to me and others not so much. For example, one new piece of information for me was the research on aphasia and second language learners, which suggests that a second language is not learned like a first language, despite much of what modern communicative language instruction suggests following Krashen who was probably influenced by Chomskyian conceptions of Universal Grammar. Even if there is an innate mechanism for first language learning (which the authors of the book also doubt — and so do I), it doesn’t appear that same mechanism is at work in second language learning.* The book highlights a number of other reasons for this beyond research on aphasics, but I’ll let you check out the book for that.
A less new to me insight, which nonetheless could bear repeating in the age when people like to talk about “the best way to learn a language,” is that “brains are as different as faces.” As such, people will all learn a little bit differently, and there is not a “best” way to learn a language for that will work for everyone.
In sum, I highly recommend the book.
* I don’t mean this to suggest that Krashen’s work was all bad. In fact, some methodology he suggests has worked well in experimental research. Only I think he gets the underlying mechanism wrong.