The Origin of Everyday Punctuation Marks

"When early scholars wrote in Latin, they would place the word questio - meaning 'question' - at the end of a sentence to indicate a query. To conserve valuable space, writing it was soon shortened to qo, which caused another problem - readers might mistake it for the ending of a word. So they squashed the letters into a symbol: a lowercased q on top of an o. Over time the o shrank to a dot and the q to a squiggle, giving us our current question mark." - Link