In certain parts of the U.S., particularly the South, we often call other guys "son". It's a colloquialism, I suppose, and used in an atmosphere of friendship.
Country music legend Jerry Reed, for one, called everybody "son".
It's easy to forget we are in a group with so many diverse languages and that to many English is certainly not their language of choice.
I am in awe of people who speak a second or third language. I've been trying to learn Spanish, but it has been slow progress.
I am fluent in Pig Latin though.

onDa asonMa