Softening a question: … vậy / thế?

Add vậy to the end of a question, most often one with a question word (gì, đâu, ai, sao, nào), to make it softer and more natural: Anh đi đâu vậy? Where are you off to? Without it, Anh đi đâu? can sound abrupt, almost like an interrogation. Vậy adds friendly curiosity, a bit like "so" at the start of an English question.

It goes last, before the address word if there is one: Cái này là gì vậy chị? Answer as usual; vậy doesn't change what's being asked.

Sao vậy? on its own means "What's wrong?" or "What's up?". The voice matters: said sharply, Em làm gì vậy? is less "What are you doing?" and more "What on earth are you doing?"

In Saigon vậy is the everyday choice, and đó is heard too: Em làm gì đó? In Hà Nội, thế and đấy are the usual choice, though many Hà Nội speakers say vậy too: Anh đi đâu thế? Ai đấy?

At the end of a statement, vậy does a different job, meaning "then, I suppose": Thôi, ăn mì vậy. Oh well, noodles it is. And Vậy à? or Vậy hả? on its own means "Really?"