How to express "Plurality" in Indonesian Language ?

A. To make a noun become plural, duplicate or repeat the noun twice
     ( rumah-rumah = houses; mobil-mobil =cars )

Repetition noun = Plural noun

For example :

• Orang-orang yang berbaju kuning berumah di sini
• Buku-buku itu berwarna merah
• Mereka berbicara dengan dokter-dokter itu

But sometimes, it's not necessary, there are two other ways to express plurality in Indonesian language :

1. It happens when the word or the content of the text stating plurality

• Buku itu menceritakan tentang makanan
• Setiap orang punya kaki untuk berjalan

2. When It's already modified by numerals and words showing quantity

• Semua orang = all people
• Banyak mobil = many cars
• Tiga orang guru = three teachers
• Beberapa komputer = several computers

B. Adding word "pada" before nouns expressing a group of persons or people

• Para dokter menemukan cara untuk menyembuhkan penyakit itu
• Para turis berkunjung ke Bali
• Saya tadi berbicara dengan para member

C. Sometimes, adjective also becomes plural by doubling the word
     in order to show that the plurality of the noun qualified by the adjective

• Di sana ada barang yang bagus-bagus
• Murid di sekolah itu pintar-pintar semua
• Para mahasiswa itu mendapat nilai yang rendah-rendah

D. Duplication followed by suffix "-an" shows variety

• Buku-bukuan ( all kinds of books )
• Sayur-sayuran ( all kinds of vegetables )
• Makan-makanan ( all sort of foods )