Hi, OP. Try seeking out these overlooked gems:
In the 1996 Uwe Boll film Enemy Mime, a Parisian mime and a performer of Swiss mask theatre are stranded on a remote Mediterranean island together and must put aside their creative differences and find a way to communicate in order to flag down help from a passing yacht. Complications arise when they're discovered by a Camorra drug-running operation that abducts the masquer and forces them to do an endless series of silent reenactments of Luchino Visconti's "The Damned."
In the 1972 martial arts film classic Yaro-U, a ninja and a samurai are stranded together on a remote sandbar in the Seto Inland Sea. Able to communicate only through their swordsmanship styles, the pair must find the correct set of forms on which to build a relationship -- and even a friendship -- before they starve to death. Complications arise when an adorable komodo dragon swims onto the island and melts the stony hearts of the brutal warriors, each of whom desires him for a pet.
In the hard-hitting 2011 sociopolitical drama Public Transit, a Republican and a Democrat coming from separate fundraisers in Manhattan fall drunkenly asleep on the subway and somehow wake up stranded in Hoboken wearing feather boas and party hats. For the sake of survival, they must put aside their differences and learn to translate each others' coded campaign-speak in order to make their way back to civilization. Complications arise when something that appears to be a poor person walks up and just starts talking to them just like that and it's super-awkward. What happens next will amaze you.
I guess those aren't particularly sci-fi'ish, though. For something more in that vein:
In the 1964 sci-fi cult hit Return to the Seventh Planet*, an American Spacetronaut and a British Spacetronaut are stranded together on a remote world in the Beta Thurii System. Theoretically they both speak English, but constant petty bickering over the correct spelling of "aluminium" and "colour" and puzzlement over why you'd call a "couch" a "settee" interferes with their attempts to get past their radically different coffee-drinker vs. tea-drinker worldviews and repair their Fuze-O-Rocket. Further complications arise when an omnipotent space alien that looks suspiciously like Michelle Angelo in a silver bikini appears from a nearby cave, and offers herself as Queen of Space to the first Spacetronaut who can serve her a glass of beer at the correct temperature.
* Fun fact: according to a guy I met in a bar the other night, this film was the indirect inspiration for the Star Trek episode "Let That Be Your Last Battlefield." At least I think that's what he was saying. It's a bit of a blur.
