Here is a good starter post about the topic by Dr. Flores on his blog, Educational Linguist. And here is Dr. Flores’ latest blog post, post- Sperry et al. article.
Here is a link to the Sperry et al. (academic) article that has reignited the mainstream “language gap” conversation.
Finally, here is a recent article from Education Week about how we must move beyond “deficit models” of low-income families and/or families of color that claim “that poor families and families of color don’t talk to, play with, or stimulate their children in the right ways and thus should be taught.”
P.S. You can (and should) follow Dr. Nelson Flores on Twitter.