"You have students."
Translation:Tu discipulos habes.
Discipuli is the nominative (plural) form (the form used when 'students' is the subject of the sentence). Here, 'you' is the subject of the sentence and 'students' is the direct object (hence the use of discipulos, the accusative plural form).
Discipuli libros habent -> "The students have books"
Does that make sense?
Are the students a THEY (= discipulae ) or a THEM ( = discipulās ) in your sentence?
If the students are the subject of the verb, use nominative discipulae ( = they're a THEY); if students are the object of the verb, use accusative discipulās (= they're a THEM).
If we use the dative of possession structure, we can say: Tibi sunt discipulae , "There are (female) students to you" = "You have students."
If we use the verb habēs , as Duolingo does, we have: Discipulās habēs = You have (female) students.
Let me know if that doesn't fully explain it.
I see, thanks for the clarification! Being a universal language, Latin had many different local pronunciations. Still, the only current institution actively using it is the Catholic Church and they are not using the restored classical pronunciation. I would have preferred to hear the ecclesiastic one but I understand the choice. It's anyway a great initiative and I enjoy the course!