Kathy Schrock proposes this categorization:
The Langwitches blog made it explicit, when it comes to apps
by modifying Schrock's illustration, adding some apps:
As a Android user myself, I cannot benefit from it, but I feel compelled to do an Android adaption later on.
After reinstalling this blog, I checked the content and realized that some of the links are not valid anymore.
BTW: I also purchased an iPad, I checked out some apps, but use it for my own professional development.