The Romanian language has a grammatical hitch similar to one in Dutch.
The Dutch language uses two definite articles. (In English, our definite article is "the.") Romanian uses two indefinite articles. (In English, we say "a," or "an" but the difference is only for pronunciation.)
In Romanian, the indefinite article for any given noun is either "o" or "un" "o" for the "feminine," and "un" for the "masculine" or "neuter."
But there is little or no indication within the noun to show that it is one gender or the other, or neither.
At least, that has been my experience in the brief time that I've spent in Romania.
But I've asked Romanian speakers, too.
What I've heard has been much like the Dutch explanation of the difference between their two definite articles, "de" and "het" the distinction is just something that you know.
The probably means that the native speakers learn the distinction by rote, but don't realize they've done so because it's their native language.