When you tell your friends that you took a swim yesterday, did you say you “swam” yesterday or that you “swum” yesterday?

Oh, come on. Everyone knows that the past tense of “swim” is “swam.” You’d use “swum” only as a past participle, usually in the sense of taking another step farther back in time: “I had swum only once before yesterday.” It can also be used in the passive sense: “The Olympic events are swum in a pool of a specified size.”

Those usages are “correct” in current English, though “swam” was often used as a past participle in the 18th and 19th centuries. Merriam-Webster’s Dictionary of English Usage says that “swum” was once used frequently in the past tense in dialect, but rarely in writing. That’s still true today.

But when you went swimming yesterday, let’s say you went off the diving board. Did you tell your friends that you “dived” in or “dove” in?

Here’s where English gets tricky. If you live in the North, you probably say you “dove.” If you’re in the middle of the country or the South, you probably say you “dived.” And if you’re British, you wouldn’t be caught dead saying “dove.” Merriam-Webster says that “dove” came about in the nineteenth century, was considered nonstandard for a time, but quickly became acceptable in the United States, though more in speaking than writing.

So grammatically speaking, either “dived” or “dove” is correct—unless your publication follows The Associated Press Stylebook, The New York Times Manual of Style and Usage, or The Chicago Manual of Style. All prefer “dived,” with Chicago saying that “dove” “has not traditionally been considered good form.” Nonetheless, “dove” isn’t wrong. It’s just not preferred in writing, though if you snuck it in, you could probably defend it.

A similar situation just “sneaked” past. Only thirty or forty years ago, “snuck” would’ve stuck out as illiterate nonstandard English, or colloquial at best. But, quoting Merriam-Webster again, “in about a century snuck has gone from an obscure and probably dialectical variant of the past and past participle to a standard, widely used variant that is about as common as the older sneaked. Some evidence suggests it may become the predominant form in North American English.”

As is true of “dove,” “snuck” is still frowned upon by most journalism usage guides, which tend to be conservative. But The American Heritage Dictionary of the English Language, published in 2006, notes: “Snuck was almost 20 percent more common in newspaper articles published in 1995 than it was in 1985.” (Chances are, it’s even more common now.) And with most dictionaries accepting “snuck” as standard and acknowledging the prevalence and appeal of “dove,” perhaps it’s time for those usage guides to dive in to the present.

Merrill Perlman managed copy desks across the newsroom at The New York Times, where she worked for 25 years.