Four features of language are displacement, cultural transmission, duality, and productivity. Displacement refers to the ability to speak about the past, present, and future as well as the real and unreal. On the other hand, cultural transmission refers to the ability of language to be learned through exposure to specific cultures. Human beings are born with innate language capabilities, but they must interact with experienced speakers of a certain language to learn that dialect (Derewianka & Jones, 2016). Duality refers to the two levels of human languages; the first level of language consists of alphabet letters and speech phonemes that have no meaning on their own, whereas the second level is characterized by the combination of various level one aspects to create meaning (Derewianka & Jones, 2016). Lastly, productivity refers to the ability of human language to evolve or be broadened in regards to the creation of new meanings and the invention of new signals to describe new ideas.
Derewianka, B., & Jones, P. (2016). Teaching language in context. New York, NY: Oxford University Press.