Why with a question mark?

From:  "alauishus"

why is it, that if you start a sentence with the word 'why' do you have to finish it with a question mark

TB helped out here: 

the question mark originated as a representation of the Latin word <quaestio>, originally 'seeking' but later 'question'. The abbreviation 'Qo' was written by scribes at the end of a sentence which was meant to be a question. Over time, with people's sloppy writing, this 'Qo' was simplified into the curlicue and underdot which is our question mark.

David K did a bit of work to find this: 

First of all, the writer of this question didn't even end his OWN sentence with a question mark!
But, in reality, I can think of an example of a sentence with the first word being "why" and NOT having to end the sentence with a question mark:
"WHY" is a 3-letter word.
That is a statement, not a question, so it does NOT end with a question mark. Most sentences starting with "WHY" are indeed QUESTIONS, so they must be ended with question marks.

pavolka shared this: 

It's a printers' convention, same as putting a comma or period inside the quotation marks and the exclamation point outside.

Sarah added this: 

when you say why at the beginning of a sentence, that means its A QUESTION!! its only proper grammar to put the question mark at the end. but hey, if you wanna start a silent protest, eat your heart out.

forrest sent us this website: 

click here!
this web site answered more than I wanted to know!?
 

Curt turned in his homework: 

If you start with a why in a sentence you don't have to end with a question mark. For example "Why, thats ubsurd!" If it is used as a conjunction it doesn't necesarily have to be used with a question mark. When not used as a interjection why indicates a question which always is followed by a question mark.

Mr. Obvious turned in this: 

Sentences begun with "Why" will always end in a question mark because they will always be questions. There's no way to make a declaration or a command when the first word of your sentence is "why."

The Saint reported this piece of information: 

Because it's what's called an interrogative pronoun (like it's cousins who, what, when, where and how), that implies a question--usually, that is. The truth is, you don't always have to. Consider the following:
•Why we don't have to use a question mark is an interesting question.
•"Why?" you ask, increadulously.
•"Why, how interesting," she said lasciviously.
(In the first example, "why" becomes the subject; in the second it's quote and the sentence continues to the period; in the last, it's just a curious speech mannerism showing remarkability rather than a question.)

Sp00k remembered he was part of the time and concluded with this: 

Why, I do believe, if I remember my grammar correctly, and you pay attention, I can answer your question.