There is no discernible gap on my wife's side of the family... they are Colombian. Further, the volume tends to increase (rapidly) as they speak over one another. I am surprised to find they are actually communicating with understanding.

same with my puerto rican wife's family. could be a hispanic thing.

slightly tangential, but on the loudness part of it, funny theory I have is that, and I noticed this when I've visited her family in their hometown, since they live outside of any big city, nature itself is so loud, they have to talk louder and louder to hear each other! ;-) especially at night, there are so many noises coming from nature itself. here in mainland US, in so many places I've been to, from Maine down to the south, from El Paso to San Fran, night time is so much more quiet! anyway, that's my theory until proven otherwise haha :)

I've lived all over the world and I suspect it's a class thing. Downtown Chicago people tend to talk over you nonstop with no regard for courtesy. Where I've been in France and the rest of Europe, it's more what you'd expect (a pause). In my rural midwestern working class background there tends to be a pause, we didn't talk over one another. My wife's family is from Guadalajara, were privately schooled and in the Mexican government's "political class", they don't interrupt.

It's ingrained in me enough that if someone talks over me, I'll just stop talking to them and subconsciously consider them to have a low standard of manners.

> San Francisco

Try living downtown. :)

My brother does this. Interrupts you, and if you don't stop speaking, his volume increases. I personally lose my train of thought and so I just can't keep up with him. But it's a fun game to play sometimes.