10 Grammar Mistakes People Love To Correct (That Aren’t Actually Wrong)

6. Using words like “slow” and “quick” as adverbs: Weird Al Yankovic has a series of videos in which he “corrects” street signs that read “Drive Slow” so that they instead read “Drive Slowly.” But, as Mignon Fogarty points out in her swell takedown of the mean-spirited tone of Weird Al’s “Word Crimes” video, Weird Al is wrong. “Slow” is what’s known as a flat adverb, meaning that it functions as an adverb despite lacking an -ly ending. Daily Writing Tips has a handy list of flat adverbs and their relationships to corresponding -ly adverbs. In the cases of “slow” and “quick,” the meanings of the flat adverbs are identical to their -ly counterparts, “slowly” and “quickly.”Robin Thicke has tried to move on from the controversy over “Blurred Lines,” releasing a…Read on gawker.​com

Here’s Weird Al on a mission to destroy flat adverbs:

Here, in Merriam-Webster’s “Ask the Editor” feature, associate editor Emily Brewster explains that flat adverbs were much more common before 18th-century grammarians insisted that words not ending in -ly were adjectives. She lists a few instances in which flat adverbs have the same meanings as their -ly counterparts and a few instances in which they have different meanings. Flat adverbs are an endangered species, in part because people keep erroneously “correcting” them.