If the universe started with a single 2 state quantum system, and has since developed solely by means of quantum mechanical processes, it follows that everything that exists is composed solely of quantum system.
'Everything' includes concepts, not just things physical. For example, the number '1' is a quantum system.
As poets know, information can have a probability distribution over a range of values, just as properties of physical quantum systems do. When a word is uttered, it means all the things it could possibly mean. Just as a physical quantum system property is restricted to a more limited set of defined values on measurement, so too can the range of meanings of a word be restricted by placing it in a context.