First of all, it's Vietnamese, not Vietnamise, and even then, it should be Viet-Namese, not Vietnamese, since the country is called Viet Nam, not Vietnam.
Two words, not one.
How'd you get Chinese right and mess up on Vietnamese and Japanese?
The difference between being called Asian or Indian boils down to, believe it or not, skin color. Generally, Asians are thought of as having yellow skin (though I have no idea where that came from. We're whiter than the white people here, who are pink), smaller eyes (a few slant, but not many of them, mind you), shorter stature (again, not all of us. Many Asians are giants by our standards), and a rather unique culture. The Asians that aren't normally thought of as Asians simply do not share much of these traits. No way can you mistake an Indian guy for a Vietnamese guy.
Why is it unfair that "Asian" doesn't apply to all of Asia? It's simply a label. Since they are in Asia, they are automatically Asians, whether they are called so or not.
And since when is the term "Oriental" derogatory? I was never aware of that "fact."
So I leave with this: If you spin an Oriental person around, does he become disoriented?