But what if you do make that trademark adjective into a noun? Why is it Curly Wurlys, not Curly Wurlies?
To answer that question, we need to understand the grammar behind irregulars.
Irregulars Follow Rules, Too
When we create new nouns, we unconsciously try to regularize their endings. The same is true of portmanteaus made from an irregular noun. Witness how we all carried Walkmans in the 1980s and ’90s rather than Walkmen. We do this because a rule is easier to remember than exception.
In The Language Instinct, Steven Pinker explains that even irregular words are governed by our word-building rules, so that when the irregular form is the root of a word, rather than the whole word, there’s an opportunity to regularize the whole word. “This layering not only predicts many of the possible and impossible words of English (for example, why Darwinianism sounds better than Darwinismiam),” writes Pinker, “it provides a neat explanation for many trivia questions about seemingly illogical usage, such as: … Why is the hockey team in Toronto called the Maple Leafs and not the Maple Leaves?”
It’s also why when you have several pieces of hardware to move the computer cursor, you have mice, not mouses. (And that’s not for the lack of trying, either. In the early days, some tried to make the plural of the hardware mouse be mouses and dictionaries still list it as an alternative, but, practically speaking, mice has won.)
When we build words out of smaller words, we look to the right for the main word—the head of the word or phrase—and follow the existing rules for that word. The head of workman, for example, is man. So the properties of man are given to workman.
But what if your term doesn’t have a head, like Walkman? It’s not a man; it’s a portable stereo system.
“A headless word is an exceptional item that, for one reason or another, differs in some property from its rightmost element, the one it would be based on if it were like ordinary words.” Walkman is headless, so it doesn’t receive the properties of either word that makes it up. Instead, we follow the regular rules of pluralizing: Walkmans.
There are a lot of examples, once you start thinking about them. Pinker offers these:
still lifes Maple Leafs
With mouse, we have a new usage of an old term, so all of the word’s traits come with it, including its irregular plural.
Pinker points out, too, that a name is not the same as a noun. “As for the Maple Leafs, the noun being pluralized is not leaf, the unit of foliage, but a noun based on the name Maple Leaf, Canada’s national symbol.” The term, therefore, is headless.
Other names follow suit. A BlackBerry is not a type of berry; a Galaxy is not a type of galaxy. Both are a type of phone. If you have more than one, you have BlackBerrys and Galaxys.
The Curly Wurly presumably gets its name from curly-wurly, an adjective that means “twisting and curling,” according to Oxford Dictionaries Online. The candy isn’t a wurly, nor is it a curly, so like the other headless names and nouns here, we’re going to regularize the ending: Curly Wurlys.
And there you have it. If you will follow trademark guidelines, you’ll have several Curly Wurly candy bars. If you won’t, you’ll have several Curly Wurlys.
Just don’t complain to me if you eat too many at once.