The movie opens with Dr. Jerome Lovell (Neeson) joining Sheriff Todd Peterson as they come upon a cabin deep in the woods of North Carolina and discover the passing of the only resident there. While looking around, Jerome comes upon Nell (Foster), who has had almost no experience with other humans. Nell speaks her own hybridized language and while she competently handles household tasks in the real world she is also living in a fantasy. Since she is of age, the local medical center want to have her come in for study, believing her to be a real Wild Child. (She's not. She was raised (lovingly) by her mother, socialized with her sister, wears clothes, cooks her food and lives in a house.)
A judge holds a hearing after Jerome spends some time observing Nell from afar. He decides to grant a three month continuance to further clarify whether Nell can live by herself in the cabin or has to go to a mental health center. The center sends Paula Olsen (Richardson), a psychology student, as a representative to observe and study Nell while Jerome takes it upon himself to continue to observe and study her as well.
Gradually, Jerome begins to interact with Nell and Nell soon begins to interact with both Jerome and Paula. They eventually learn from Nell that she had a twin sister who died when the pair were young. When a newspaper reporter learns of, and comes upon Nell in her cabin, Jerome and Paula decide it is safest to take Nell to the hospital. This decision is forced when a helicopter representing a television crew comes upon the cabin. When she arrives at the medical center, things go bad for Nell.
The movie resolves in a courtroom scene where the argument of Nell belonging in the mental health center or being able to live in her cabin comes to a head. The rights of an individual versus social management, preconceived notions and assumptions, and not judging by surface appearances are among the themes of this surprisingly complex film.
Tropes used include:
- Character Tics: A heavy use by Nell, particularly lifting her arms over her head and using her arms to mimic physical gestures to her dead sister.
- Character Title: The title of the movie is named for the main character, Nell.
- Child by Rape: It's revealed through old newspaper clippings that Nell and her sister are the result of their mother's rape.
- Deep South: It takes place in North Carolina, but the movie is quick to utilize crude redneck stereotypes who express sexual mockery of and towards Nell. There are also gentle, decent Southern types, especially good-natured Sheriff Peterson, his troubled but sweet wife Mary, and Simple Country Lawyer Don Fontana.
- Do Not Go Gentle: Nell accepts that everybody dies and that she will eventually die. Ties in with her courtroom speech.
- Dumb Struck: Nell becomes mute after her visit to the medical center.
- Eloquent In Her Native Tongue: Once you realize that Nell uses Biblical words and phrases in a heavy North Carolina accent, mingled with her mom's aphasic traits and a secret language from her childhood, she becomes almost completely comprehensible.
- Fan Disservice: Nell in the bar room, when she exposes herself despite the verbal taunting thrown at her. (It's clear she thinks the boys are just being playful and showing her a new dance.)
- Fanservice: The scenes where Nell skips over the rocks and proceeds to dive into the lake... although this comes off more as Maxfield Parrish fairylike, not sexy.
- Home Sweet Home: Nell and her cabin in the woods, to the point of it being featured strongly in the final scene of the movie.
- Mood Motif: Dr. Lovell plays a Patsy Cline song, which causes Nell to run back to her cabin — she's never heard amplified music like that before. Later, when in the town, Nell hears country music coming from a bar leading to the above Fan Disservice scene. Mark Isham's score includes a hammered dulcimer, evoking traditional country life.
- Mr. Fanservice:
- Dr. Lovell strips down and goes Skinny Dipping with Nell.
- Early in the film, when Dr. Lovell is hauled out of bed by a phone call, Neeson has a nice shirtless moment.
- Papa Wolf: Dr. Lovell develops this attitude towards Nell, including physically shoving two people for just interacting with her (although one deserved it and the other scared the daylights out of her with his flash camera).
- Parental Abandonment: Nell's mother raised her and her sister by herself without a father figure. Paula's father abandoned the family when she was a child.
- Rape as Drama: About ten minutes into the picture, Dr. Lovell is given a news clipping revealing that Nell's mother was raped and she attacked the man who did it when he was caught. He realizes her mother became pregnant this way.
- Sinister Surveillance: One of the first things Paula does is install cameras in Nell's house while she's sleeping. Jerome is furious when he discovers them, but doesn't make her remove them. He even asks her if she saw how Nell spoke to him for the first time.
- Stupid Scientist: "Experts" at Paula's presentation, including Paula at this point, watch a film of Nell communing with her dead twin sister May via mirror. Since they don't realize there's a twin, they think she's saying "me" in her thick Carolina accent, rather than "May." (The loving chant between the sisters includes the words 'tay and may,' and it's only when Nell whispers the chant with Jerry and Paula's little daughter that it's revealed to be 'Thee and me, thee and me.' Nell and May could even have been playing with 'May/me' in their twin language.) Cue the psychobabble explanations: "She has an objective self and a subjective self" and her gestures are "some kind of self-comforting."
- They Would Cut You Up: Jerome doesn't want this happening to Nell and remonstrates with Paula and Dr. Paley about their wanting to bring her into the hospital.Dr. Paley: Because you can't take a baby and have it grow up in a lab.Jerome: You want her to grow up in a lab?note
- Unresolved Sexual Tension: Occurs between Jerome and Paula throughout the movie. Heavily hinted attraction from both sides to the point that Nell seems — or at least Paula thinks she does — to interpret an argument between them over her status as "parents arguing," and forces them to make up.note
- What the Hell Is That Accent?: Nell picked up a very strange and unique accent from living alone for many years with a mother who already had a North Carolina Piedmont accent you could cut with a knife, and could only talk out of one side of her face following a stroke. Even without the twin-language vocabulary, her speech is so unique and incomprehensible that it could hardly even be called English any more.
- The one that drives viewers crazy is chickabee, missa chickabee. Chickabee is a variant on "chickabiddy," which goes back over a century as an endearment. Nell has adapted it into chicka for "dear" or "beloved" (she says chicka so at the hearing, which Jerry translates as "loved ones". Perhaps so is "soul"). She shows Jerry that missa is "little". "Little darling" or "little dear" is all it means. She has really adapted English, combined it with her and May's twin language, and created a creole.