Just tap the picture of the desired item/action/question/etc.
So simple, but so powerful.
You can say anything! From basic needs to a whole phrase.
Let's say, as an example, that the user wants to sleep.
This is how he can say it:
Step 1. Tap the "I need" button Step 2. Tap the "to sleep" button
...and the iPad will say the message: "I need to sleep"