Ispeech


A great tool that converts text to speech is iSpeech.
 
iSpeech

Personal (non commercial) use is free and is great for visually impaired students. You can either use the demo at the front of the site for quick text to speech, or you can sign up for a free personal account that lets you do much more such as embed text to speech in your website.

iSpeech could also be good for language and literacy learners.