When she entered Children's Hospital at the age of 14 -- still in diapers -- Genie was the size of an 8-year-old with the language and motor skills of a baby, speaking only a few words -- including "stopit" and "nomore."
Her discovery coincided with the premiere of Francois Truffaut's film "The Wild Child," about an 18th century French "wolf boy" and the doctor who adopted and tried to civilize him.
Riveted during a private showing of the film, the staff assigned to Genie's care applied for a grant from the National Institute of Mental Health to study Genie's rehabilitation.
The hottest academic issue of the day was the 1967 Lenneberg theory that maintained that children cannot learn language after puberty. In some ways, Genie disproved this, but she had passed the "critical period" and was never able to master grammatical structure.
From 1971 to 1975, a multidisciplinary team used Genie as a case study -- "Developmental Consequence of Extreme Social Isolation" -- under the direction of Dr. David Rigler.
The team was mesmerized by her charisma and curiosity. Susie Curtiss, just out of graduate school in theoretical linguistics, was a member of the team and worked with Genie on language acquisition.
"I was a very young woman given the chance of a lifetime," Curtiss, now a professor of linguistics at UCLA, told ABCNEWS.com.
"She wasn't socialized, and her behavior was distasteful, but she just captivated us with her beauty," said Curtiss, who took the child on daily outings.
Because of the Genie study, doctors now know that grammatical development needs linguistic stimulation. When children are isolated from language, a window closes and they lose the ability to speak in sentences.
"I spent most of my time being a human being, relating to her and we fell in love with each other," Curtiss said. "I wasn't old enough to be her mother, so I was able to be somewhere between a sibling and a parent. Genie was just amazing."
Curtiss described Genie as "highly communicative," despite the fact that she spoke fewer than 20 words at the onset. She often made her needs known by gesturing or other means, and she loved being stroked and hugged, and learned to hug back, according to Curtiss. When she was upset, at first she had a "tearless cry," but eventually she "showed emotion very clearly."
In her textbook, "Genie: A Psycholinguistic Study of a Modern-Day Child," Curtiss described how Genie eventually could use limited language to describe her father's cruelty: "Father Hit Arm. Big Wood. Genie Cry."
Believing that a loving home would help Genie's development, some of the specialists became her foster parents. At first psychologist James Kent became a father figure. He had argued unsuccessfully that Genie should not be separated from her mother, the one emotional attachment in the child's life.
Soon, Jean Butler, Genie's nursery school teacher while in the UCLA study, took the child under her wing. But Butler, who has since died, became obsessed with making a name for herself, Curtiss said in a 1994 documentary called "The Secret of the Wild Child."
According to Curtiss, Butler told colleagues she wanted to be the next Annie Sullivan -- the so-called "miracle worker" who taught language to the blind and deaf Helen Keller.