Richard M. Roberts and Roger J. Kreuz, Becoming Fluent: How Cognitive Science Can Help Adults Learn a Foreign Language (2017). (notes)
How did I find this book? Accidentally. I was searching for a copy of a paper, Susan Brennan, The Grounding Problem in Conversations With and Through Computers, which is collected in Social and Cognitive Approaches to Interpersonal Communication. I found that book in Google Books, and in the "related books" section I saw Becoming Fluent. "Roberts and Kreuz report evidence that adults can learn new languages even more easily than children." OK—sold. When I found out the St. Louis Public Library had a copy I jumped right into the queue for it.
The authors start out with three myths they intend to tear down:
Myth 1: Adults cannot acquire a foreign language as easily as children.
Myth 2: Adults should learn foreign languages the way children learn languages.
Myth 3: When learning a foreign language, try not to use your first language.
Sounds good—I need all the help I can get.