Except many languages’ vocabularies share common roots (e.g. Latin and Greek) even if the languages themselves don’t, so quite often someone learning Spanish will be able to make an educated attempt at figuring out the equivalent Spanish word (for instance, an English speaker might figure out that machine ≈ máquin_)… but will have no clue about the gender, having a 50% chance of ending up with, say, máquino.

And, as I said, misgendering words seems to be a relatively common mistake for people learning Spanish without having a Romance language base.