My institution subscribes to the "Kurzweil Reading Program", a "Text-to-Speech" product for those with reading impairments (dyslexia, English language learners, blind/vision impaired, etc.)
Section 121 indicates these users are "eligible persons" for "fair use", but others, without such disabilities could use the program (like an audiobook in the car!).
This question reflects the level of savvy "Ask the Lawyer" readers bring to their submissions. The member submitting the question has already set out (in a manner much more succinct than I usually achieve) the interplay of: