Directors Pierre Coffin and Chris Renaud wrote a language for the gibberish the minions speak throughout the film. They called it "minion-ese". Each word the minions speak in the film translates into an actual word.
The film was animated in the French studio Mac Guff in Paris, and although a U.S. production, it was written and directed by Spaniards and Frenchmen, making Despicable Me (2010) a very cross-cultural production.
The name of the main protagonist, Gru, appears to be taken from the Russian Military Intelligence agency GRU. GRU is an acronym for Glavnoye Razvedyvatel'noye Upravleniye (roughly translates to Main Intelligent Department/Directorate), the foreign military intelligence directorate of the Russian Armed Forces. It is the largest Russian intelligence agency, six times larger than the SVR (formerly the KGB). This may hint at Gru's own origins.
The girls undercharge Vector when they deliver his cookies. Based on the clipboard Margo is holding when they pay him the initial visit, the prices of each of the box of cookies is thus: Coconutties - six dollars, Choco Swirlies - six dollars, Minty Mints - six dollars. Vector ordered four Minty Mints, fifteen Coconutties, two Toffee Totes, and two Caramel Clumps. The Minty Mints and Coconutties alone would cost one hundred fourteen dollars, plus the cost of the Toffee Totes and Caramel Clumps, means that the girls charge of only fifty-two dollars, was way below what it should have been.
For those who are really into details: Gru's first name is Felonius. His parents were Marlena and Robert. His fraternal grandparents were Joesph and Helen. Through them, he has and uncle Jeffrey and a step-uncle Steven (a jungle explorer) from his grandmother's previous marriage. He also has a great-uncle named John. His maternal grandparents were Henry and Madeline. Henry had a brother Helmut, who was married to Jane. They had a son known only as convict 3619. His great-grandparents on his father's side were Able and Antoinette. His great-uncle Henry's parents were a Gypsy named Yolanda, and Marcel, who was a werewolf. Yolanda's parents were Art and Lucy. His great-grandmother's parents were Elixabeth, and a soldier named Oliver. Oliver has a daughter, Little Pony, and a son named Charles. Oliver had a cousin named Willian (a mad scientist), whose parents were Mareva (a Pacific Islander), and a one-eyed sea Captain named Ron. Gru's greatgrandparents on his grandfather's side were Mathid and Francois. Prancois' parents were Charlotte and Leopolde, Mathid's parents were Sara and a mountain man named Jack. There you have it: all six generations. (Taken from the family tree chart on the wall in the hallway near the girls' bedroom.)
One of the pictures hanging on the walls of Gru's house (it can be seen when the three girls first enter the house, next to the front door to the left), is a "Wanted" poster for the capture of Jesse James, a notorious Wild West gunman and bandit.
When the girls first get adopted by Gru, Edith says, "when we got adopted by a bald guy, I thought it would be more like Annie." This is ironic because Dana Gaier, who voices Edith, played the role of Annie in her school's 8th grade production of 'Annie.'
When Gru first walks into his house after getting coffee in the very beginning of the movie, his TV is on. It appears to be an interview with Sia, which is weird because she didn't get popular until 2014.
When Gru is telling the girls the rules and gives number three, he uses a hand gesture which is correct sign language for that number. Most people use other fingers, indicating Gru knows some sign language.
When the Minions go to the store to get the replacement toy, there is a scene in which the "baby" shakes up a bottle of soda, puts it in his mouth, hilarity ensues. On the shelf behind him, the labels on the bottles read, "POP (then in much smaller letters) soda," and the word "POP" is arranged to make the cheeky joke of creating the word "POOP." One can assume this must be intentional, as the word "pop," which is necessary for the joke, is used pretty exclusively in a small part of the upper Midwest.
When Vector is seen playing video games on the Wii, he holds the controller in his left hand, indicating that he is left-handed. This may be a subtle reference to his villainous nature, because another word describing left-handedness is the word "sinister".
The trivia items below may give away important plot points.
While Gru is floating in space, while orbiting the moon, we see that the number on Gru's "Swan Lake" ticket is 072069 - July 20, 1969 is the date of first moon landing, which Gru is seen watching in flashbacks.
After the girls' bedroom has transformed into a more comforting place, the camera angle allows the audience to see some famous paintings that Gru has stolen. Leonardo Da Vinci's "Mona Lisa" hangs on the wall, and Vincent van Gogh's "Starry Night" can be seen leaning up against the wall on the floor.
May 26, the day around which the entire film revolves - it's the day of the girls' dance recital, the capture of the moon, and the big chase to rescue the girls from Vector which leads to Gru and the girls becoming a family - is the birthday of Steve Carell's daughter, Annie. Elisabeth Anne Carell, who was Steve and wife Nancy's first child, was born Saturday, May 26, 2001. He said in 2008: "When Elisabeth Anne was born six years ago, something inside me just snapped and my perspective on what was important changed overnight."
There is a nod to a scene from The Godfather (1972). The morning after Gru has "given" the girls back to Miss Hattie. He reveals the playdoll hairdresser head and begins to scream and gesture in the same manner when a bloody horse head is discovered in the sheets.
The scene where Nefario flies after Vector's ship to rescue Gru and the girls, when he says "there he is", appears to be a nod to Star Wars: Episode V - The Empire Strikes Back (1980), when Lando Calrisian flies the Millenium Falcon up under Cloud City to rescue Luke, and also says "there he is". In both scenes, someone is hanging precariously, and they are surrounded by clouds with a low sunset type of lighting.
Gru shares some characteristic features with the DreamWorks character "Megamind". Both are introduced as villains, and end up being the hero of their respective movies, both have great intellect they use to create high tech weapons and gadgets, and while Gru has an army of Minions at hand, Megamind's most trustworthy and loyal ally, is a talking fish in a robotic body, called "Minion".