I have trouble with choking on saliva, also, at times. Seems like little bits and little things can be a problem swallowing, big things and regular eating isn't.

I figure it's the little things that slip down unnoticed that get caught, when I'm not paying attention and it isn't big enough to get my throat to recognize "something's coming down, pay attention and send it the right way." The epiglottis is weak or "lazy" and lets little things like a bit of saliva or a tiny bit of food (those last couple rice grains that didn't go down with the rest) slip through because it wasn't triggered to do its job by the feeling of a big mass coming its way.