Affirmative word order in questions
Oscar from Colombia writes:
  When can we use affirmative word order in questions?
Roger Woodham replies:
Declarative questions
We use affirmative word order in questions in spoken rather than written English. Declarative questions can be used when the speaker is fairly sure he has understood what has been said, but he just wants to make sure. In declarative questions, a rising intonation at the end is common:
You're going by plane? I thought you were going by bus.
You've already bought the tickets? I thought you were broke.
Note that if the declarative question consists of more than one clause, a rising intonation is less feasible:
You think we should keep the money even though we know it's been stolen?
When you ask a question in the declarative mood, you expect the answer to be 'yes'. However, if you use a negative construction, you expect the answer to be 'no':
You've never been to Paris? ~ No, I haven't.
You've been to all the other European capitals? ~ Yes. ~ But never to Paris? ~ No, never. ~ That's extraordinary!
Note that questions expressed in the declarative mood often begin with the conjunctions so, and or but:
His behaviour has been good whilst he's been in prison. ~ So you're quite satisfied with his progress? ~ Reasonably satisfied, yes.
You're keeping his medicine in the fridge? ~ Yes. ~ And you'll make sure he takes it three times a day? ~ Yes.
You say you heard funny noises? ~ Yes. ~ But you didn't see anything suspicious? ~ No.
Note from the travel example questions above that we often use the declarative mood to express surprise. Here we are repeating what has already been said and, by using a rising intonation, we turn it into a question:
I've never been to Paris. ~ You've never been to Paris? Such a romantic city!
Did you know Wills and Kate have split up? ~ They've split up? I thought they were definitely an item!
We can also use this strategy to focus on one part of the sentence and put a question word at the end of our declarative mood question. Note that word order is not affected:
She's invited 250 guests to her wedding. ~ She's invited how many?
They're going to Belo Horizonte on honeymoon. ~ They're going where?
She's pawned her pearls to pay for it. She's pawned what?
Reported speech questions
Note that we also retain affirmative word order when we are reporting questions in indirect speech:
What's the matter?
I asked her what the matter was.
Why are you crying?
I asked her why she was crying.
When did he leave?
I wanted to know when he had left.
Who did he leave with?
I wanted to know who he had left with.
Note that question marks are not used in reported questions. They are, of course, essential in declarative questions as they are the only indication on paper that a question is being asked.
Eiffel Tower