To prepare for her role, Mélanie Laurent worked as a film projectionist for a few weeks at New Beverly Cinema, projecting mostly cartoons and trailers before shows. The real test set by Quentin Tarantino was for her to screen Reservoir Dogs.

Approximately 42% of the film is in English, the language which dominates the film is German. Chapter Three of the film ‘German Night in Paris’ is devoid of English. This is highly unusual for a Hollywood production. Christoph Waltz’s character speaks the most languages in the movie out of anyone else in the cast: four (English, French, German, and Italian).

Michael Fassbender’s performance as Lt. Archie Hilcox is layered with irony due to his real life. Fassbender was born in Germany to German and Irish parents and raised in Ireland, now residing in London with fluency in German as his first language and English as his second, and a mastery of English accents and dialects. Here he plays an Englishman who goes undercover as a German, and who can speak German fluently, but cannot hide his accent.

Eli Roth put on 35 pounds of muscle to play Donnie Donowitz, “The Bear Jew” and learned to cut hair for the role from producer Pilar Savone’s father Umberto at his salon in Beverly Hills. When asked how he got into the violent, baseball bat-wielding mindset of “The Bear Jew”, He partially attributed his performance to the historically accurate costumes: “Being in wool underwear will make you want to kill anything.” He also stated (in a separate interview) that his girlfriend had secretly added some Hannah Montana music onto his iPod; when he listened to it, it inexplicably made him able to tap into the violent nature of The Bear Jew.