I'm an American who lives in Japan. I can speak Japanese reasonably well, but I normally keep my Google Home speakers and Google Assistant app set to U.S. English for ease of use. Now I'm thinking of buying Google-compatible smart ceiling lights for my livingroom from a Japanese manufacturer. (In Japanese homes, most rooms have a universal attachment in the ceiling that accepts any style of ceiling light - the U.S. needs to learn that lesson!) But of course the example voice commands are all in Japanese - I'm sure they are assuming all their users have their smart speakers set to Japanese. I asked a light manufacturer about it, but they merely answered that their lights are only for use in Japan and therefore they have not tested them with English and cannot advise me.
So my question (thinking like a programmer) is: When a voice command is given to Google Home to control another device (e.g. "Dim the lights in the living room"), I know Google Assistant will first parse the sentence to determine which device(s), e.g. the room called "livingroom" and device type called "lights". But then, does it send the rest (in this case, the word "dim" in English) to the device as-is, or is there an underlying code that is not English or Japanese at all but part of a common command set for smart lights? I know that I might have to experiment to figure out what English syntax works with any given model (particularly fancier stuff like changing the color temperature or setting the brightness to a specific level), but I just want to know if it's possible.
This is actually the second IoT device I've bought in Japan, but the first was only a cheap plug (so the only commands are on and off) and all its communication was through Smart Life (almost certainly a server in China, and it supports multiple languages), so that's not a very good test.