My dog is a loud swallower. Not when he eats his food and not when lapping up water. Nope. Just randomly when he's sitting there waiting for me to prepare his dinner or after he looks up at me from a cozy little dognap. *GULP*
It's like he's either perpetually worried that I've caught him doing something or he's just a gulper. I don't think that it's equivalent to a human mouth-breather or close-talker because its mildly endearing. Like when he scares himself awake with his own flatulence.
I just haven't figured out the trigger. Does he have an overactive salivary gland? Does he always think he's going on some harebrained adventure? Human gulpers show their true colors when the seat bar locks them into their roller coaster seat, or right before they step off the high dive. But canine gulpers? This shall require more research.