My Gear is stock rooted, and I have a note 2. I just went from n3bula rom to Beans' new Alliance rom - I would swear on n3bula it didn't do that. I don't use s-voice a ton, but it feels like I would have noticed the Gear speaking "I didn't catch that". It reads out like three different things when you send a text message. Doesn't matter if it's sound/vibrate/mute, and I can't find any options to shut that off anywhere...
Am I just dumb or blind? God I hope so...that's really annoying.
-- edit --
Turns out it was both dumb and blind - open s-voice on the phone, lower left-hand corner has the option to disable voice prompts, which includes the Gear. I'm actually glad nobody replied to my silly question.