Accessibility options allow Android devices to be used easier by folks with impaired vision, hearing or motor skills. Options like inverted colors can help us see what's on the screen better, Screen Readers can tells us what we're not able see ourselves, and motion and gesture support makes things more friendly for those of us who might not be able to hold a phone or tablet and tap controls at the same time. There are plenty of options that make things more accessible built into Android, and manufacturers have added to them in many unique and ingenious ways.
While things are getting better with each and every iteration of Android, there is still a long ways to go. That's where third-party apps and the way they can integrate into the core system on Android comes in. There is plenty of room in Google Play for apps like keyboards or maps that can help those with special accessibility needs, and this is an area where we hope things can keep growing.