My dog also used "outside" + "water" to express her need to pee. I would be inclined to agree with you if she couldn't use them in the abstract, but she can.

Realizing that making the sounds for "outside" allows you to go outside is not very far from language. I see people saying this every time dog buttons come up and it's very curious to me. What exactly do they need to do, model the parts of a sentence?

language is simply a form of communication between 2 beings. If those buttons are pushed so that a specific outcome may occur through another party (human) I would qualify that as a form of language.