If we consider spoken language as a complex linear system, we will be able to use it as a pretty good standard for understanding individual psychology as well as interpersonal communication.
All words have words associated with them. Though we all share many of the same word-associations (coffee/beverage; booze/drunk; etc.), we also all have an abundance of word associations that belong only to us. I suppose this is fairly obvious, though I am not so sure it is well enough appreciated.