I love the use of floor puzzles and large-scale floor activities to academically engage kids with nonverbal autism. It allows them to move freely, plus studies have shown that movement can improve learning.

I used floor puzzles to teach my son the alphabet and beginning sounds. Recently he got one of his floor puzzles out and put it together, and agreed to help me create a video to share our technique.

You can find alphabet train floor puzzles on Amazon at these links:

https://a.co/d/e4z6quf

https://a.co/d/hOemW9p

If the above links expire, simply search "alphabet train floor puzzle" and new links will appear.

My son loves it when I make up silly songs to teach him new things. You can copy my song or make up your own - I didn't put a lot of thought into it, I just made it up one day on the fly. There's nothing scientific behind it, so feel free to improvise. 

To quiz your student's alphabet knowledge, you can play a game where you ask them to go stand by a specific letter. This allows them to show mastery of an academic subject without requiring them to speak or write.

Nonverbal Autism Homeschool shows you to use physical hacks like this to teach your student real academics. Enrollment is always open!