"A lányok diákok."

Translation: The girls are students.

[Icreatedyou]

What kind of a student is diak? Primary-Uni?

[Uborkas]

It just means student, not a particular level. I was an exchange student in Hungary, and we were called cserediak

[killerman64]

mit csere?

[MrtonPolgr]

While it's true that it can technically refer to both, I think it's worth mentioning that for university students, there is the word "hallgató" or even "egyetemista" so indirectly, not using those words makes me associate diák with an elementary/high school student.

[alyssums]

what would the difference between saying "the girls are students" and "the students are girls" be in a sentence like this?

[mizinamo]

• A lányok diákok
• A diákok lányok

Pretty much as one would expect, given that you have "the" in front of "girls" in one of your sentences and in front of "students" in the other, and the predicate (are students, are girls) comes second and has no article.

[TamirElaza]

How would you say "the girl students"?

[MrtonPolgr]

Sounds quite rare English for me... I'd go with "a diáklányok" probably.