Millions of people use HP calculators with their RPN notation. That doesn't speak directly to prefix notation, but certainly suggests that people can learn another syntax without much problem -- even if there is something about our innate linguistic skills that favors some particular syntax.
Right, RPN is another door we should open in K-12. We had a poster awhile back sharing his Python RPN module as I recall. I downloaded it and played with it some. Certainly I was a big fan of HP and using parentheses-free entering the way RPN allows. HP calculators were also what first exposed me to the concept of a stack (RPN goes togther with a stack concept). When minds are young, open, flexible (that's the stereotype anyway -- analogy with bodies) is a good time to keep thowing out alternatives, other ways of thinking. So I'm wholly in favor of early exposure to prefix notation, in a addition to RPN. If a student starts experimenting with an altogether new notation, having learned the less that these are technologies we can just _invent_ (not handed down as eternal practices that weigh us down forever with legacy notions), I'll take that as a very positive sign. Python's ability to override (aka overload) syntactic elements such as + * () [] and give them new meaning provides further encouragement in this direction. As one of the Scheme websites put it, you want your language to be more like the problems you're thinking about, so you do some language customization, vs. always trying to make the problems conform to the strictures of some unalterable given. Kirby