Answer:
Genie's case supported the notion of critical period in language, because she could not aquire any useful language because she had missed the critical years of early childhood development due to complete isolation from the outside world.
Explanation:
She wouldn't make it to the total adquisition of language even if she had acces to help or instruction. The first five years are the most important years of development, which language is one of the basic functions. The critical period in language acquisition lasts until the age of 12 according to the linguist Eric Lennenberg. According to Lennenberg, after the age of puberty, it is hard to acquire anymore meaningful vocabulary skills. Before Genie's case, it was hard to determine who was right in the "nurture vs. nature" debate. Nurture meaning that language is learned by one's environment. Nature meaning that one is born with the ability to learn language, and that they can learn it very quickly at any time in their life. Genie's case (along with other feral children cases like Isabelle, Anna, and Danielle, to name a few...) proved that it depends on ones environment for their ability to learn language, and if you miss the critical ages of early childhood development, it is next to impossible to acquire any useful language skills.