As I understand, your main concern is for the narration of the backgrounds and scenery, and not with ordinary character talk and action declaration.
My approach would be to build a common reference base within the group. You all probably have movie, reading and/or video game experiences in common. So why not refer to these when you describe scenes? E.g. "The army stands silently on the side of the forest clearing when the messenger arrives ... as before the opening battle of Gladiator." or "Your perception keeps snapping back and forth between reality and enchantment, as Danny Kaye's did in the fencing scene in The Court Jester." If you do this, there sure will be players who know the scene you are talking about, and will be able to reflect to it, to add details and to relate it to the others who may not know it. You can suggest each other stuff to watch and read for the next session. Also, visual information is much easier to grasp and remember than words, so referring to movie scenes will also have the beneficial side effect of conjuring up much more vivid images than words and descriptions, and so the party will have a better time of getting the gist of how things really look like. The players can also do this to describe their actions ("I'm scaling the wall like Errol Flynn."). In our gaming group, we do this for great effect, though we all speak our native Hungarian so language is not a barrier (e.g. for a 7th Sea Montaigne court scene, we had the storyteller watch the movie Vatel, and it added much to the story).
Speaking of visual info, you may also bring pictures and props to your game to show the players (or music and sound effects). This will not only help with the understanding, it will make the gaming experience much more profound.
Writing a vocabulary is a good thing as long as it is not a list and is easy to consult. Write the vocabulary on where it belongs: scenery adjectives on the specific locations on your map, character adjectives on the respective NPC sheets, etc. This way, whenever you are introducing something, the words will be there at your fingertips.