Thank you for the explanation, though the underlying requirements for keeping a list locally appear to remain much the same, since you really only need to add a few trigger words to the "dumb, always-on" local parser (such as your top 1000 advertisers' company or product names). After all, I'd imagine we do not require context, but only really need to know whether a word was said or not, not unlike listening for the "real" trigger word.

This is of course only one of many ways to attack such a problem, and I do not know how they ultimately would do, assuming that they were interested in listening in on their users in the first place.

And yes, embedded devices are slightly harder to fiddle with than using your own computer, but I'd bet that they didn't actually take the time to make a proper gate array and instead just use some barebones Linux, which most likely means UART access!