"The Painted Bird," the first-ever movie in Slavic Esperanto - a created language - premiered at the Venice film festival this week.
Set somewhere in rural eastern Europe towards the end of World War Two, the black and white film is a sombre tale of a young boy trying to survive a harsh wilderness and the cruelty of strangers.
Director Vaclav Marhoul said he specifically chose a kind of Slavic Esperanto for the villagers' dialect.
"I didn't want the villagers (speaking) Ukrainian or Polish or Russian or something like that because those people (the villagers in the film) are really bad people," he said.
"I didn't want that some nation is going to be associated with that, so I opened the big brother - Google, big brother, and typed 'Slavic Esperanto', my God it does exist, it does exist, Slavic Esperanto."
The invented language combines Czech, Russian and German.
Based on a 1965 novel by Polish-born novelist Jerzy Kosinski, the film depicts a bleak world where being different is dangerous.
Sent by his persecuted parents to stay with an elderly woman in the desolate countryside of an unnamed country, the lead character, known simply as The Boy, soon finds himself alone when she dies and he sets off on foot to find safety elsewhere.
He wanders from village to village, where he meets and stays with different people - some of them superstitious and cruel, others accommodating and kind.
In one key scene, one of The Boy's hosts paints the wings of one of his captive birds and releases it into its flock, only for it to be attacked by the others.
"(The film) depicts Europe at a very dark time, but it's a dark time that is not specific to that time, that is sort of existing today all over the world in many places," actor Stellan Skarsgard said.