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The symbol is generally thought to originate from the Latin qu ¦stio, meaning question, which was abbreviated to 'Qo'. The capital 'Q' was written above the lowercase 'o', and this mark was transformed into the modern symbol.
There is another theory about the origin of the question mark. It may have originated from the 9th century, when it appeared as a point followed by the curvy bit written slanted, like '.~', although the ~ was tilted more upward to the right. The point has always indicated the end of a sentence. The curved line represented the intonation pattern of a spoken question, and may be associated with a kind of early musical notation.
In some languages, most notably in Spanish typography since the 18th century, every question mark must be opened and closed; an interrogative sentence or phrase begins with an inverted question mark, " ¿" and ends with the familiar question mark "?". However, this orthographical tradition is often disregarded in quick typing, especially in chat rooms and Internet forums, and where the inverted character is not easily available from the keyboard.
The rhetorical question mark first appeared in the 1580s and was used at the end of a rhetorical question. It was the reverse of an ordinary question mark, so that instead of the main opening pointing back into the sentence, it opened away from it. This use disappeared in the 1600s.
The question mark is also used in Chinese and Korean.
In chess notation "?" denotes a bad move, and "??" a blunder.
DALE
