http://chronicle.com/img/photos/biz/linguafranca-45.pngBy . The hashtag is a major innovation in language. It was invented just a few years ago, to allow quick and easy categorizing of tweets. And then hashtags became an easy way to comment on the topic of a tweet, as in You had one job: A show about a detective with OCD, and that’s how they designed the box for the last season. #wellplayed Often a hashtag is a comment on a comment: I’m done with science #stopcorrectingparties2k14 Im extremely obsessive about everything I love Fall Out Boy so much #Superwholockian #soccer #softball #nickyrubio #random Destiel is my life Acknowledging its importance to linguists, the American Dialect Society chose #hashtag as its Word of the Year 2012. Two years later, the society recognized hashtags as a separate language category and promptly chose the hashtag #blacklivesmatter as Word of the Year 2014. Surveying the various uses and forms of hashtags nowadays, I was going to claim that a hashtag has no grammatical limits. It can be a complete sentence, an isolated word or two, an abbreviation, an emoticon—anything your keyboard will allow. More...