Lexical Constraints on the Formation of -er Nominals Derived from Intransitive Verbs

The English suffix -er has long been considered as a morpho-syntactic diagnostic for split intransitivity since -er nominals are derived only from verbs that have external arguments. Therefore, the formation of an -er nominal derived from an intransitive verb should be based on an unergative verb (a verb that have an external argument) instead of an unaccusative one (a verb that have an internal argument). As split intransitivity is syntactically represented but semantically determined, the formation of -er nominals is actually semantically predictable. Two approaches in the literature, the projectionist and gradient approach, give a detailed explanation for the semantic constraints on determining a verb' argument as either external or internal. Compared with the projectionist approach, the gradient approach seems to offer a better account to predict some verbs are more consistent in forming an -er nominal while others exhibit variation.