The fake version of Persian spoken in the film was invented by the director and a Russian linguist, who developed a grammar and a 600-word dictionary.
"Joon" means dear in Farsi and is not a family name; Reza, however, is a name. So, "Reza joon" means "dear Reza."
It was Belarus' official submission for the 'Best International Feature Film' category of the 93rd Academy Awards in 2021, but was disqualified by the Academy because the majority of individuals involved in making the film didn't come from Belarus.
The text "Inspired by True Events" appears on screen at the start of the film. The "true events" in question likely refer to World War 2 and the Holocaust, as the specific story and characters of the film are fictional and is, as the credits mention, adapted from the 1977 short story "Erfindung einer Sprache" (Invention of a Language) by German author Wolfgang Kohlhaase.
The film's script was first written in Russian, then translated into English and eventually into German.