We've got character analyses for the Captain and Liesl, but what about the rest of the gang?
Obvious ancestors of the Partridge Family, Captain von Trapp's other children all seem very pleasant and amusing in their own right, but they don't get nearly as much character development as Liesl. Like Liesl, they start out being skeptical of Maria's role in the house and play tricks on her. They can't resist her for very long, though; they warm up to her big time and are devastated when she runs back to the abbey.
Oh, and by some amazing coincidence, they can each sing very well.
Here's what we know about each of the non-Liesl von Trapp kiddos:
Gretl von Trapp
She's the adorable youngest child, and very sweet. She takes to Maria right away and warns the new governess not to believe the other children's lies. She's five years old at the beginning of the film and sometimes doesn't like being the littlest.
Her voice sounds like the love child of a kitten and a unicorn.
Marta von Trapp
She's almost seven when we meet her, and she wants a pink parasol for her birthday. Talk about character development.
Brigitta von Trapp
She seems to be a bit of a bookworm, since she has trouble tearing herself away from her reading when Captain von T summons the children to meet Maria. She compliments Maria for not falling for one of Louisa's tricks, but then insults Maria's dress as the ugliest ever.
Not gonna lie: we kinda agreed with that one.
Louisa von Trapp
Louisa's the main trickster of the bunch. When she's introduced to Maria, she pretends that she's Brigitta (Maria doesn't fall for it). Also, we learn that she's able to climb up to the governess's room with a jar of spiders in her hand. She apparently honed that skill while hazing one or more of Maria's predecessors.
Kurt von Trapp
Kurt is the younger of the two von Trapp boys, and announces that he's "incorrigible" when he first meets Maria. He doesn't know what that means, though, so it seems that someone else called him that.
Freidrich von Trapp
Freidrich is the oldest boy, and apparently is "impossible" according to a previous governess. It's unclear what he did to deserve that title. Maria feels he's trying hard to learn to be a man but isn't getting any help from his father.
At least before Maria comes to town.