GM: A portcullis falls in front of you.
Player: I attack it ... with my +2 sword
Other player: I don’t think that’s going to cause any damage
Player: Why not, it’s +2 to damage?
Yep, actually happened. And yes, we teased that guy about it for years. Probably tells you more about the cruelty my friends and I inflicted upon each other than anything else. By modern day standards we all would have been expelled for bullying and violating his “safe space”.
Anyways! Look, not every player knows every vocabulary word. Not every player knows your world so well that they will know that the Lats have black hair and the Bortens have red hair. The simple point is this - While we stress realism and storytelling through FRPG, please always remember that it’s a game. It’s a hobby and the players have different levels of interest in the various aspects. Yes, after a tease or two, I actually pulled out the rule book and showed the player where a portcullis was defined and priced so he would understand what we were talking about. Always remember that fun is more important than the facts, and I have yet to meet a person who played FRPGs because they wanted to learn vocabulary.
We’re not saying dumb everything down. Instead we’re saying that you need to make certain you are not demanding more of your players than they are willing to give. Explaining things in more than one way is not cheating; it’s good game mastering. You won’t need to do this every time, but you will sometimes.
The best way I’ve found to do this is to reveal more every time a question is asked. The more mature me as GM would have said: A portcullis falls in front of you. OK, this portcullis is an iron grate with iron bars, so even though your sword is magical steel, you will probably not be able to batter your way through. These bars are like three quarters of an inch thick, so ... Sort of saves the embarrassment, but still describes what’s going on for everybody, because chances are, there’s more than one player who didn’t read the price list of castle parts before the game.