I've watched a lot of those videos, and it seems to me that the animals are trying to communicate what they want using the buttons, and seem to understand that there's some message being communicated when they press the button. I doubt they understand sentence structure - it seems more like a toddler's understanding of language at best. Think about a human toddler going "want up!" Or "Dada, juice!". But that's still pretty impressive, I think. I've been thinking about getting some, since one of my cats will stand next to the cart of cat supplies and just yell at me until I figure out by trial and error if he wants catnip, brushies, a toy, etc. If he could press a button to tell me what he wants, that would be better for both of us lol.