Ranger has some treat dispensing puzzles that he seems to really enjoy. The other day out of curiosity when we were playing with a puzzle I signed What Is That? indicating the puzzle. Ranger signed Food quickly followed by making the sign for Toy. I can easily see that as an intentional combination of signs he knows to say that what I wanted him to identify was a toy that gave him food. For me FoodToy would be a reasonable categorization of the puzzle but does it really mean the same thing to him? Perhaps he meant it not as a compound word but as identification of two different things the puzzle itself was a Toy but inside the toy was Food and he didn't know which one I wanted him to identify. Or maybe he didn't know how to answer the question so signed both Food and Toy hoping one would be right.
I truly believe other species like dogs have something like language as I know it but how much that language corresponds to the language I use and understand that's the real question. And this is where it is so nice not to have to hold myself to scientific standards, because I'm doing this strictly for us (myself and my canine) I'm free to assume that his language use corresponds to mine and Food Toy meant FoodToy. I am sufficiently concerned with scientific accuracy that I feel obliged to recognize that my assumptions may not be correct.