Thank you for calling my attention to Gary Simpkins' research about dialect readers in elementary-school reading instruction. Learning to read proficiently is extremely important for African-American students from a highly oral cultural background because it can enable them to undergo the kind of aural-to-visual development in cognitive processing that Walter J. Ong writes about in Ramus, Method, and the Decay of Dialogue: From the Art of Discourse to the Art of Reason (Harvard University Press, 1958). Also see Ong's "World as View and World as Event" in the American Anthropologist, volume 71, number 4 (August 1969): 634-647.
As you may know, John McWhorter discusses Ong's most widely known book, Orality and Literacy: The Technologizing of the Word (Routledge, 2002; orig. 1982), in Doing Our Own Thing: The Degradation of Language and Music and Why We should, Like, Care (Gotham Books, 2003, pages 20, 38, 39). However, McWhorter does not happen to discuss Ong's account of the aural-to-visual shift in cognitive processing.
The aural-to-visual shift in cognitive processing that Ong writes about is connected with the actuation of cognitive potential the kind of cognitive ability measured, however imperfectly, by IQ tests, especially the kind of cognitive ability that Arthur R. Jensen refers to as Level II. What he refers to as Level I cognitive abilities are as well developed in children who come from a strongly oral cultural background as in children who come from a more visually oriented cultural background. But Level II cognitive abilities are not usually actuated in people from a highly oral cultural background unless and until they have individually undergone the aural-to-visual shift. For this reason, Simpkins' research about reading instruction is best understood as involving the aural-to-visual shift in cognitive processing that is connected with actuating cognitive potential of Level II. Nevertheless, we do need to remember the tendency known as "backsliding" because individual children from a strongly oral cultural background can indeed make short-term gains on IQ measures as the result of intensive educational programs, only to have those gains disappear after the students leave the intensive educational program.
In my 1983 article "IQ and Standard English," as you may know, I am a happy heretic from the orthodoxy in linguistics because I attach a certain significance to the use of the standard forms of the verb "to be." The standard forms of the verb "to be" epitomize the visualist polarity in cognitive processing the world-as-view sense of life. But the non-standard forms of the verb "to be" usually express the world-as-event sense of life.