"Successful communication = cognitive modeling (Licklider, 1968). When people have a manipulatable model in front of them,they utter few words, point, nod etc." (I'm not sure how much of this is a quote, so I'm putting it in quotes just in case. Need to check above source)
For a machine, "knowledge" about data structures, what collections of its bits and bytes are called and what they can do with them, this is analogous to our sense of our arms and legs, how to call upon them and what they are capable of. Even when a programmer talks to a computer in its language, it doesn't really understand them like a Swiss understands an American speaking Swiss-German.