  Theories of natural language and concepts have been unable to model the
flexibility, creativity, context-dependence, and emergence, exhibited by words,
concepts and their combinations. The mathematical formalism of quantum theory
has instead been successful in capturing these phenomena such as graded
membership, situational meaning, composition of categories, and also more
complex decision making situations, which cannot be modeled in traditional
probabilistic approaches. We show how a formal quantum approach to concepts and
their combinations can provide a powerful extension of prototype theory. We
explain how prototypes can interfere in conceptual combinations as a
consequence of their contextual interactions, and provide an illustration of
this using an intuitive wave-like diagram. This quantum-conceptual approach
gives new life to original prototype theory, without however making it a
privileged concept theory, as we explain at the end of our paper.
