Casio's don't come bundled with Text to Speech readers but I've always been intrigued by the concept of using existing Braille Reader or TTS technology to interface with the ASCII displays on many models of modern keyboards.
While the task of engineering a kludge interface for such a device is not beyond the skills of a good electrotechnologist or electrical engineer for most sightless mortals the cost of such a custom solution is still out of reach.
One possible workaround, however, might be an Android or Apple iPhone or tablet using software such as Kurzweil's Reader to capture and vocalize the displays.
It may not work perfectly and glare from ambient lighting could mess up the reader I think it is the only viable solution for anyone who is visually impaired.
Otherwise, however, I think it is shameful how most keyboard manufacturers ignore the needs of the partially or fully unsighted.
It would almost be trivial to add on a simple ASCII interface to vocalize or braille output a standard display if there were an industry standard.
To make matters worse, the trend in modern keyboards is large, graphical, touchscreen displays so god only knows what solutions may be feasible in a decade or two.
Gary