Booij's
semantic extension schema (Booij
1986) attempts to account for polysemous meanings of affixes diachronically without resorting to the
Separation Hypothesis. He proposes that the suffix
-er, for example, entered Dutch as an Agentive marker. Its meaning then predictably extended to nonanimate Subjects and from there to Instruments, e.g.
spel-er 'player' >
bijsluit-er 'enclosure' >
open-er 'opener'. See Beard (
1990) for a response.
