In which case you can pick a different wake word, which they mention in the video. I don't know what those specific alternatives are, but I'm betting just about everybody will be able to find one that doesn't match a housemate.

I wonder if all the alternative words have a "hard" sound in them. Like the X in alexa.

The way I think they work is they constantly record 2 seconds of audio, and look only for peak "hard" sounds. Like K in Ok, and X in Alexa. If they find a peak they search back to see if the word was the one they are looking for, but otherwise the CPU is mostly sleeping.