how do children learn langage?

I think the way children learn language solely depends on the child's upbringing and the more attention from parents to help their child cognitively the easier a child will find it to pick up language. A study I have looked at is the study of genie and genie was a child who was neglected by her parents, not just love and care but also she lacked and contact of speech with her parents, the effect of this left genie unable to ever grasp forming sentences because of her amount of neglect, her brain missed any opportunity to develop in the crucial stages of her life when she needed it so it was too late and her brain size physically decreased as her brain was getting no exercise leaving her unable to form any sentences. Although when she was discovered she was able to learn some words with the help of  phsycologists but that's as much help she could get. I think the main way children learn language is from their parents and with out this nurture it can have a negative effect on a child's future, starting children with easy mono sylabic words helps for a child as it slowly brings them into language and using objects and games helps children a lot too because children are visual learners.