The case of Genie is a significant study on the impact of extreme environmental deprivation. Discovered at age 13 after a decade of severe isolation, Genie was unable to speak or stand. Following her rescue, her abilities improved, and she managed to acquire an impressive vocabulary in a relatively short time. However, she never mastered the grammatical aspects of language. This specific difficulty with grammar, despite her vocabulary growth, is often cited as evidence for the critical period for language acquisition, suggesting that the opportunity to learn fundamental language structure may be lost if missed in early childhood.