It does contain at least one use of the word “arse”.
Are you only counting British films? Because Gone With the Wind famously used “damn” in 1939.
Some of the language used in the original script of “Saturday Night - Sunday Morning” was not allowed in the film by the censors. The words “sod”, “Christ” and “bogger” (a euphemism for “bugger”) were all considered too strong at the time.
Going to be pedantic and point out that you mean general release movies. I’m pretty sure four-letter words were used in porn.
But yeah, we have to pin down what you mean by “four-letter words”. The “damn” that was so scandalous in Gone with the Wind is considered completely innocuous today.
The Big Parade (1925)
“This is believed to be the first film in which the word “damn” is used by a character (albeit on a title card).”
"Due to Hollywood censorship of the time, title-writer Joseph Farnham had to tone down the salty dialogue of the American soldiers. For example, he was required to substitute “b------s” for “bastards”. Yet in another scene he was allowed to have John Gilbert shout (in all caps) “GOD DAMN THEIR SOULS!” - The Big Parade (1925) - Trivia - IMDb
An “Oh, Shit!” made it into the Laurel & Hardy short Perfect Day (1929) at 13:00.
In 1969 the film “Kes” was released. It contains quite a lot of swearwords, including four-letter words referring to male and female genitalia, but was quite surprisingly released with a “U” certificate because at the time an “A” certificate would have barred anyone under 16 from seeing it unaccompanied by an adult.
According to Imdb there is an undubbed version of the film containing the F word.
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How times change: I recently saw the movie Wicked Little Letters (with Olivia Colman and Jessie Buckley), which is a feast for connoisseurs of the sweary (I forbear to post the trailer, which on its own is exceedingly NSFW, but it is on YouTube)
My Fair Lady used it four years later, of course.
Echoing Gone with the Wind, the 1972 film X, Y, and Zee has the line “Frankly, I don’t give a shit”. But these are both well after 1060.
The 1953 film The Moon is Blue was famously the first major film to use “virgin” (it’s even as plot point in an episode of M.A.S.H.), but it’s also the first to use “Seduce” and “mistress” (in a sexual form), according to IMDB.
Apparently there’s a video called Movie Munchies that features clips of early swearing in films. The actual sources aren’t named in websites, but it’s claimed:
That’s interesting, if true. I’m amused that Cary Grant, in Arsenic and Old Lace has to shout “I’m a Son of a Sea Cook!” in the film, instead of his character saying “I’m a Bastard!” as he does on stage.
(Playwrite Joseph Kesselring and his purported ghost collaborators must have gotten a high out of having a character who is a theater critic shouting that.)
Are you aware that at one time most of the World thought that Americans always slept in their underwear?
This impression came about because that was how they appeared in films.
Wait a minute. That’s the impression I currently have and I’m an American. What (if anything) do most Americans wear to bed?
I have to believe that the occasional curse word sneaked into silent films early on, to the delight of lip-readers.
Pajamas?
Those are for wearing to school now.
…or the complaints. In The Habit of Happiness (1916) Douglas Fairbanks is shown telling some dirty jokes with salty language to a crowd of men. The title card just says, “That reminds me. Did you hear the one about…” and “Note- We’d like to let you in on this story but it takes Mr. Fairbanks himself to put it over right.”
Lip readers were outraged and the film had to be pulled from distribution and the scene re-shot before re-release.
People wear clothing to bed?
The Petries did.
I’m pretty sure every film ever made had plenty of 4 letter words, (barring maybe one where no spoken language is used at all, but I can’t think of an example.)