Punctuation Dot Dot Dot

Sometimes a punctuation mark is more than a punctuation mark. Period.

You undoubtedly caught what I just did there, using the word period as an adverb or interjection to emphasize my point. And voilà: a punctuation mark being more than a punctuation mark.

I first became interested in the life of punctuation marks as words, rather than squiggles on a page, when I learned about how younger speakers are using slash as a coordinator. It got me wondering about how many punctuation marks have taken on...