Humans appear to be born with an innate universal grammar. Learned Culture is transferred across generations through teaching and learning. Anthropologists call this enculturation. Education in the broadest sense is at the core of this process. Shared Culture is socially constructed.
Language is arguably the most basic component of culture.
There is no such thing as a private language. Adaptive Culture changes over time in response to alterations in the environment, social development, contacts with other cultures, etc. Cultural adaptation over time creates history. Adaptation has allowed humans to survive and prosper in a wide range of environments. The differences that characterize human societies is also what makes contacts between cultures so complex and, often, difficult.