I've created this app for one of my family members who's not able to speak but can move their hands and point their fingers, it helped them communicate with everyone and is good muscle exercise for the fingers.
Then decided to publish it for others who might benefit from it as well as take suggestions on improving it for everyone as well as adding features that could help with different disabilities.

It supports any screen size (Tablets Preferred) and scales accordingly.

Feel free to review the app and comment your suggestions.