Unnatural

Here's a sentence from a recent Onion.com review of a movie called Confetti:

The three couples include a brittle, hyper-competitive duo planning a tennis-themed ceremony; a sweet but stressed couple trying to keep the bride's vain dancer sister and the groom's insufferable rocker buddy from taking over their musicals-themed wedding; and a mellow nudist pair fighting to keep their wedding au naturale in spite of the magazine's distaste.

When we borrow words from foreign languages, we generally do whatever we want to them--change their meaning (slightly), their spelling (a bit), or their pronunciation (usually a lot)--with flair and abandon. We might leave them alone--"soigné", for instances, with accent mark and pronunciation intact--or we might mess around with them (we often drop the first accent mark from "résumé", and alter the pronunciation to match--"REZ-oo-may"). When we borrow entire phrases, however, we generally keep them intact: "hoi polloi", for instance, or "auf Wiedersehen". Why, then, is "au naturel" so repeatedly bullied about?

"Au naturel" is the French for "in its natural state: as it is", and is often used in English to mean "nude", but can also mean "in a natural fashion", particularly when applied to food. It's not entirely surprising to see it rendered "au natural", because "natural" is the correct English spelling and in fact that's how the phrase is sometimes pronounced in English (though with the stress moved to the last syllable). But "au naturale"? Where did that come from? It's not English and it's not French--it isn't even Spanish. It's made up-word, some English speaker's idea of what a French word ought to look like, and for a professional writer, that's just careless.