Should sentences like “I wonder…” end with a question mark?

Question

This may be related to a general grammar rule, but which of these is correct?

I wonder if Steve Jobs will be giving the keynote speech at WWDC this year?

or

I wonder if Steve Jobs will be giving the keynote speech at WWDC this year.

My hunch tells me the question mark is incorrect, but I find myself instinctively wanting to add it. Is there a rule about this type of situation?

Answer 1

Your hunch is correct. Bryan Garner writes:

Writers sometimes err by putting a question mark after an indirect question, especially one beginning with I wonder.

^{Garner's Modern American Usage}

Answer 2

If you are asking a question, then yes. If you are simply telling people what you are wondering about than it isn't a question and it should not have a question mark.

Some examples to help clarify:

I often wonder about the future.

I wonder what is for breakfast.

I wonder... who is that?

People will often say phrases like these as asking a question but its usage can be considered awkward for written English.

I am curious about your name?

That is pie?

And you are?

The question marks here are more flagging the intonation we use in everyday speech. You can also use an elipsis:

And you are...

Your name is...

On tests you will see a blank line:

The answer is _____________

But for "I wonder..." I would stick to a period/full stop. When you say it out loud, feel free to say it much like you ask a question.