A student sends a question via email. He heard the answer “tidak apa-apa” (it’s ok) when he asked the condition of his friend (an Indonesian), which fell from the bike. He asked the use of two-word question ‘apa’ in that sentence.
In Indonesian language, to show ‘plural’ (plural) are made by repeating the word.
• Guru saya punya buku-buku tentang Indonesia. (My teacher has some books about Indonesia) (more than one book)
• Meja-meja ini harus dibersihkan sesudah pesta. (These tables should be cleaned after the party). (more than one table)
Similarly with the question words.
• Dia sudah ke mana-mana. (He has been to everywhere). (to Malioboro, Borobudur, Kraton, etc.)
• Toko itu ada di mana-mana. (That store is everywhere). (in Yogyakarta, Jakarta, Singapore, etc.)
• Dia bukan siapa-siapa. (He is not whoever). (not a teacher, president, director, etc.)
In the word ‘tidak apa-apa’ has meaning sick, not wounded, not dead, etc.. The word ‘tidak apa-apa’ also means ‘tidak ada masalah’ (no problem, it’s ok).