I’m pretty sure humans need physical contact with other humans to survive. I think they’ve done some experiences with chimps or monkeys or something, and without that, they literally didn’t survive. But, that’s not really what you’re asking. You’re saying, take a bunch of humans, start fresh, what happens.
I agree that they would develop language – in Nicaragua, they put all the deaf children together and didn’t teach them sign language, and within a few years, they had created their own Nicaraguan sign language, fully syntactical.
@engineer_comp_geek, here’s my cite:
The scheme achieved little success, with most pupils failing to grasp the concept of Spanish words. The children subsequently remained linguistically disconnected from their teachers, but the schoolyard, the street, and the school bus provided fertile ground for them to communicate with one another. By combining gestures and elements of their home-sign systems, a pidgin-like form and a creole-like language rapidly emerged — they were creating their language. The “first-stage” pidgin has been called Lenguaje de Signos Nicaragüense (LSN) and is still used by many who attended the school at the time.[when?]
Staff at the school, unaware of the development of this new language, saw the children’s gesturing as mime and a failure to acquire Spanish. Unable to understand what the children were saying, they asked for outside help. In June 1986, the Nicaraguan Ministry of Education contacted Judy Kegl, an American Sign Language linguist from MIT. As Kegl and other researchers began to analyze the language they noticed that the young children had taken the pidgin-like form of the older children to a higher level of complexity, with verb agreement and other conventions of grammar. The more complex sign language is now known as Idioma de Señas de Nicaragua (ISN).
I agree that an isolated human wouldn’t develop that, or might not even survive, if they were isolated from birth. But, a group of humans, born and raised together by aliens, would likely create a language.