It's mean "a/an" in English. We can say like this "kamu makan apel" and "kamu makan sebuah apel" but we rarely used, kamu makan sebuah apel. Every Indonesian knows if you said kamu makan apel, it's mean singular noun. If you say like this: "kamu makan apel-apel" it's mean you eat an apples. In our language we translate, you eat an apple jadi: kamu makan sebuah apel. But in reality we always said like this "kamu makan apel". We don't need v1-v3 in our language.
I am Indonesian native speaker. In our language we only used SPOK (Subjek, Predikat, Objek, Keterangan). No v1,v2,v3. Also for plural noun we used repeatable words such Berulang-ulang (repeatable), ikan-ikan (fishes), ayam-ayam (chickens). In singular just "ayam" and "ikan". We don't have verb tenses. It's make our language and other Austronesian language such as Malay, Javanese, Sundanese, quite simple. But I think for many westerner they always confused with our language especially in the term of future or past tenses words because we don't have such thing.