As the speaker of an English language me can tell you is not a difficult.

...because its the articles which are not gendered, not the nouns.

Because recognising when to use "a", "the", or 0 article is tricky.

A/an is usually fine. 0 article and the are tricky, and then getting it right on the fly is hard.

We take it all for granted and get it, but they're hard for people who don't have an equivalent in their first language.