Translation:There are two big pockets on this shirt.
Is it really that different in saying "pocket in my shirt" as opposed to "pocket on my shirt"?
What is the purpose of having the particles に and は in this sentence? Why not just に?
Consider a situation where you're out shopping with a friend and she's trying to convince you to buy a shirt with no pockets. You've been talking with her about this pocket-less shirt for several minutes. You spot a shirt you like much better, because it has pockets, and tell her:
"This shirt has two big pockets."
That's the point of には. It adds a certain emphasis, highlighting the fact that you're talking about "this shirt in particular," where as に would simply be you making an observation that a shirt has two pockets.
Why is ookii used with na ? Shouldn't it be ookii pocketo ? Ookii is not a -na adjective ?