Readers of a certain age might remember a similar issue with Apple’s “Think Different” advertising campaign in the 1990s, which had thousands of people crying, “No, think differently!” More recently, singer and grammar nerd “Weird Al” Yankovic has been seen changing a road sign from “Caution Drive Slow” to “Caution Drive Slowly.”
The good news is that there are readers who recognize that an action verb (like sleep or think or drive) should be modified by an adverb, not an adjective. The bad news for people trying to use correct grammar is that there are times when what looks like an adjective actually is an adverb, called a “plain” or “flat” adverb.
Let’s take a closer look at these little known modifiers with examples from Marvel’s Avengers.
(If you need an adverb review, see the posts that covered the basics of adverbs and adverbs that don’t always end in ly.)
The Merriam-Webster Dictionary of English Usage defines a flat adverb as “an adverb that has the same form as its related adjective.” This covers adjectives that have an adverb form both with and without ly (e.g., bright/brightly, slow/slowly, deep/deeply), and adjectives that are the always spelled the same in adverb form (e.g., fast, long, far, straight).
Adjective: Hawkeye took a quick look at position of the robodogs.For adverbs that can be spelled with or without the ly, sometimes the meaning is the same, and sometimes the two forms have different connotations or can only be used in specific instances. In the Hawkeye/Natasha example above, both adverb sentences could use either “quick” or “quickly.” Try switching the adverbs in these examples, though:
Flat Adverb: He shouted down from the roof, “Get up here quick!”
Adverb: Natasha grabbed for the fire escape rung. “I’m coming as quickly as I can.”
Adjective: Tony picked up speed flying the straight lines of Manhattan’s streets.
(Always) Flat Adverb: Of course it was harder to fly straight with Captain America clinging to one side of the suit.
Flat Adverb: Hawkeye aimed right at Loki’s head.You can see that sometimes the ly version and flat version have different meanings. The last example contains the answer to our original question. You can smile tightly, or you can fasten something down tightly with a wrench, but there are certain idiomatic expressions like “sit tight” or “sleep tight” that only work with the flat adverb. Fortunately, they are still grammatically correct.
Adverb: “You are rightly angered, friend,” Thor said, stepping between them.
Adverb: “You’ve hardly been out of the workshop all week,” Bruce said.
Flat Adverb: “Working hard to keep you all in Pop Tarts,” Tony replied absently, spinning a schematic.
Flat Adverb: “Sit tight, we’ll have you out of there,” Natasha said, while Hulk lifted a chunk of concrete rubble.
Adverb: Steve nodded tightly and waited to finish being unpinned.
Flat adverbs used to be far more prevalent. The about.com page on flat adverbs quotes examples from Robinson Crusoe that sound archaic today: “the weather being excessive hot”; “extreme hot”; “the sea went dreadful high.”
Today flat adverbs are more common in informal speech, particularly in the American South, where the ly is often dropped. Because of the perception that flat adverbs are adjectives being misused, in formal writing it is preferable to use the ly version wherever either version would be correct. On the other hand, if you are writing dialogue for a character who does not speak in formal English, flat adverbs may sound more natural.
To determine whether a particular adjective can be used correctly as a flat adverb, check the dictionary. If the definition includes an adverb section, it may note that the adverb usage is informal, or dialect, or archaic. Decide accordingly whether it would be appropriate in what you are writing.
Grammar Girl: Do All Adverbs End in "-Ly"?
Macmillan Dictionary Blog: Flat adverbs are exceeding fine