It's hard to imagine how dogs think, and until we know for sure, the possibilities for speculation are almost endless. Do their thoughts come out in disjointed fragments, or in their own personal dog vernacular? Do they start every word with the letter "R," or do they have almost no vocabulary? Maybe they talk in code through the wagging of their tails, or maybe their barks are encoded.
Garth Stein must have himself wondered about it all when he was crafting this story, and the effect of choosing such a refined style for Enzo makes him that much easier to relate to. It also makes him a humorous and engaging narrator.
Enzo is a very articulate dog. He takes the time to show us that he knows a thing or two about pop culture and human forms of entertainment. His language tends toward the eloquent when he talks about his own emotions or when he is pondering the state of the world—he himself would use "pondering" over "thinking about"—and he loves to draw parallels between racing and human life.
Enzo doesn't feel the need to over-describe everything around him. He minimally describes settings and people—just enough to set the scene—and spends more time on emotional states, his own and those of the people around him. Since he can't always know everything about what's going on around him, some events are ambiguous, while others seem so clean-cut and obvious it's hard to wonder what the humans around him are even thinking.
Stein has no problem giving Enzo a clear bias toward his family, and as such, Enzo also tends toward the dramatic when something upsets him.
He's certainly not afraid to speak up when something doesn't feel right. In an Enzo moment that does a great job of showcasing his personality, he describes Annika, sitting at a coffee shop with her friend:
At Bauhaus, she sat at an outdoor table with another girl. At this hip and cool coffee shop in our neighborhood, she sat drinking coffee and smoking cigarettes! She was at least seventeen by now, possibly eighteen, and was legally allowed to function in society on her own. Technically, she could sit in any coffee shop in any city and stew in her wretchedness. I couldn't stop her. But I didn't have to deal with her—immature finger pointer, inflictor of wounds! (51.12)
We hope all dogs are that dramatic, because it's both adorable and hilarious.