Hey

While some (my wife) feel that my son's first word was "mama," I think he finally had a conversation as he answered my "hey" with a "hey" of his own.
This went on for what was probably a few hours before we both tired of the exercise.
"Hey."
It's a grand example of pith and concision. My son only says what is necessary and leaves verbal gristle on the floor where it is meant to stay.
Hey, My son is a genius.