The Opensource NVDA (nvaccess.org) screen reader (and likely JAWS, as a commercial product) will read on-screen text.

Accessibility is also dependent on the types of content and markup people use in their surveys (for example, if they add an image, and don't use ALT text to describe an image, then the image isn't accessible). And some question types like dynamic sliders and Google Maps integration will inherently present accessibility issues and thus should be avoided in your surveys.