Question 1

Why isn’t there a word for “is” in Buku itu tebal?

Accepted Answer

Indonesian often uses a zero–copula in simple descriptive sentences. You don’t need a separate verb “to be.” So Buku itu tebal literally reads “Book that thick,” but means “That book is thick.” In formal contexts you could insert adalah, but it’s rare before adjectives.

Question 2

Why does itu come after buku? Could I say itu buku?

Accepted Answer

Demonstratives in Indonesian—ini (this) and itu (that)—always follow the noun they modify. So you must say buku itu (“that book”). Itu buku would sound awkward or wrong.

Question 3

What if I want to say “this book is thick”?

Accepted Answer

Simply swap itu with ini:  
Buku ini tebal.  
(“This book is thick.”)

Question 4

How do I make it plural: “the books are thick”?

Accepted Answer

Indonesian indicates plurality by context or by repeating the noun. You can say:  
• Buku-buku itu tebal. (“Those books are thick.”)  
• Or even just Buku itu tebal if it’s clear you mean several books.

Question 5

Why is tebal placed at the end of the sentence?

Accepted Answer

In Indonesian, adjectives follow the noun (and its demonstrative). The order is:  
noun → demonstrative → adjective.  
So you get buku → itu → tebal.

Question 6

Does tebal change for gender or number?

Accepted Answer

No. Indonesian adjectives are invariable. Tebal stays the same regardless of singular/plural or masculine/feminine subjects.

Question 7

How can I say “That book is very thick”?

Accepted Answer

Add an intensifier like sangat (very) or colloquial banget:  
• Buku itu sangat tebal.  
• Buku itu tebal banget.

Question 8

How would I turn it into a question: “Is that book thick?”

Accepted Answer

You have two common options:  
1. Add the question marker apakah:  
   Apakah buku itu tebal?  
2. Use rising intonation only:  
   Buku itu tebal?

Buku itu tebal.

Breakdown of Buku itu tebal.

Questions & Answers about Buku itu tebal.

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Master Indonesian — from Buku itu tebal to fluency