 In the late 1960s Richard Montague showed how the semantics of significant parts of natural languages could be handled with logical  tools.[20]  One of his main insights was that noun phrases (NPs) can be interpreted as sets of subsets of the domain, i.e., as (what we now call) type \({\langle}1{\rangle}\) quantifiers. Montague worked in type theory, but around 1980 a number of linguists and logicians began to apply the model-theoretic framework of logics with generalized quantifiers to natural language  semantics.[21]  Consider the structure of a simple English sentence whose subject is a quantified  NP:[22]