Most of my student are non-verbal or limited verbal in my class, I promote Say It, Sign It, or Show It. Say It either verbal or with a speech generated device. Sign It using ASL or show it with gestures or pictures.

Here is a board I created in Boardmaker Plus so that my students can learn to alert me and my staff there is a need. Of course, the students have to learn the meaning by making associations with the picture/word combo which is when teaching the meaning by creating or using situations to help students make connections.