The other kind, aka the “Active listener”; or the one always listening. Would be used to listen once activated by the passive listener, and has a much more broad vocabulary. However, these are online only. Due to the way they work (gathering metadata to increase accuracy), its just not possible currently on a small device. Examples would be standard APIs such as Google, Wit.ai, Ivona/Polly, etc.
There are projects to fix these offline issues, but they are all in the works. See my site for info on some of them. mattcurry.com