With listen without keyword phrase activated, it is amazing how often casual conversation in the room will trigger an action on the computer. Of course this always happens at the worst possible moment, and can drive you crazy until you figure out what's going on.
As to the number of syllables in the keyword phrase, my preference is to keep it short and distinct. So you got me to thinking about what makes a good keyword phrase for dictation commands. A quick search in Google turned up the following recommendation from Apple.
...For best results, use a word or phrase that has three syllables or two to five words.
I found lots of articles on how to turn dictation commands on, but virtually nothing on choosing good keyword phrases. I have a friend on the faculty at a nearby university in the field of communication and I think I'll pose this question to her and see what she comes up with.
