I disagree with all of you.
When I started gaming, I was eleven. There were many words I was introduced to for the first time via gaming books, and I had to look them up, process them, and understand them before I could really grasp the underlying concepts they represented. When I started playing old World of Darkness games at around fourteen, that presented even more extreme challenges.
Many of the words that are traded on in gaming fairly liberally are still mystifying to people outside of the fandom or gamer communities. But tabletop gaming is a reading-intensive hobby that requires being introduced to a massive lexicon of words that don't enter the average citizen's vernacular. The same could be said of many hobbies, but gaming, especially, by virtue of the breadth of words dedicated to its creation, demands an expansive vocabulary. Not to punish or keep out those who don't understand, but to give them a compelling reason to learn.
If we stop raising the bar of the understanding of the young and the newest additions to the hobby by insisting we create a dialog using only the words they can easily understand as a child, we do them a disservice by depriving them of the educational benefits of gaming, and we do ourselves a disservice by gutting one of the most positive, beneficial side effects of the hobby.
Edit: Almost all of you. Big ups, Raphael.