Is Toshi actually speaking Japanese?

I'm curious, could you clarify something for me? The paragraph mentions "Toshi" and the question of whether or not he's actually speaking Japanese. Now, I'm not a linguist or an expert in language identification, but it does make me wonder - how can we be sure that Toshi is indeed speaking Japanese? Are there any specific indicators or clues in the text that point towards his language being Japanese? Or is this just an assumption based on his name or cultural context? I'd appreciate any insights you have on this matter.