Hadhaa Kitaabun vs. Haadhal Kitaabu

One question that plagues many new students of the Arabic language is the difference between hadhaa kitaabun and hadhaal kitaabu

The difference is best demonstrated by example: hadhaa kitaabun kabiyrun means “this is a big book,” and “hadhaal kitaabul kabiyru” means “this big book …”

Get the difference? The first (hadhaa kitaabun) is talking about any book. “This is a book.” Nothing special. The second–hadhaal kitaabu–is talking about a specific book. It’s saying “this book … something.”

And how do you know the difference? in the second case, the book is definite–it’s a specific book. Notice, al-kitaabu–the book. Not kitaabun–a book.

And, notice the second one is a fragment–this big book what? This big book is open? This big book is on the table? And so on.