Read and Write for Google is an excellent Chrome app that provides text-to-speech functions from your browser. They have just released a free iPad and Android app.
The apps provide text to speech functions, which are great for ESL, learning disabled, visually challenged and struggling readers, on your device, just like the web app does in the Chrome Browser and Chromebooks.
There are some other features that are available also, either with a fee or by using a Google Apps for Education account.
Google for Education Resources
Google Accessibility Features in Chrome (OS and Browser)
Android for Education Resources
Evernote Clearly gets Text-to-Speech - premium only