There are many Text-to-Speech tools on the market. A while back I was looking for one that had some very specific features. I was programming a Springboard Lite (www.prentrom.com) and I wanted to use synthesized speech rather than digitized so I needed to be able to generate a .wav file from the text, as well as create a child's voice. On top of that, it needed to be, if possible, my favorite price, FREE! After a good deal of searching I found Balabolka, http://www.cross-plus-a.com/balabolka.htm. Not only does this fully featured TTS program read text remarkably well, but it highlights, exports to a variety of audio formats, has a variety of skins that can be used to increase visual readability, and has a magnifying tool! There is also a stand alone version that can be used on a USB without installing! The author distributes Balabolka for free, but encourages you to purchase his other products in order to keep it free. I am not sure about the safety of Share-IT, but as soon as I am I think I will purchase his other product, as I am sure to do many Balabolka installs this year!
Check it out, play around with manipuating the voices. I programed a button on one student's device just recently, with a scary sounding whisper for his job at a park with a location called "Death Hollow!"