One out of six adults in the United States possesses low literacy skills. Many advocates believe that technology can pave the way for these adults to gain the skills that they desire. This article describes an adaptive intelligent tutoring system called AutoTutor that is designed to teach adults comprehension strategies across different levels of discourse processing. AutoTutor was designed with a simple, easy to use interface that caters to the special technological needs of adult learners. Though the interface may be simple, the functionality is not. AutoTutor leverages empirically based learning principles from cognitive psychology to scaffold the acquisition of reading comprehension skills. In particular, it embeds six major learning affordances, or learning opportunities, that help students master difficult material. We provide an overview of AutoTutor, describe its learning affordances and discuss its potential as a reading comprehension tool. We conclude by considering some of the challenges when building adaptive technologies to support low literacy adults. [This paper was published in: "HCII 2019," Lecture Notes in Computer Science (LNCS) Vol. 11597, edited by R. A. Sottilare and J. Schwarz, Springer Nature Switzerland AG, 2019, pp. 327-339.]