That's something to keep an eye on. You want to write in English, and probably not even forsoothly, but there are words that will pitch your more knowledgeable readers right out of the story. And even with your less knowledgeable readers will not pick up on how smoothly you sidled your world-building into your style unless you actually do sidle it in.
By such little effects as having archers not firing their arrows. Arrows are firing only by analogy with guns (which really do fire), and therefore, you need to have guns to use.
And no one should refer to the subjects of a kingdom as citizens, and lovers should not talk about their "relationship."
The biggest thing to keep an eye on, in my experience, is the metaphors. Especially dying metaphors that are embedded in the language. World-building would keep you from introducing a game of bridge in a world with no cheap paper and consequently no playing cards. But an eye on your language is necessary to keep you from saying that a certain mage's strong suit is fire magic.
And sometimes you can't use legitimate stuff. "To broadcast" once meant to cast seeds broadly, throwing them out over the field by hand. But no one's going to know that when you use it in a pseudo-medieval setting. (sigh)
It's a counsel of perfection, but it's worth keeping an eye on it.