We show that graphemic variation—at least in some writing systems—can be analysed in terms of grammatical variation given a usage- based probabilistic view of the grammar-graphemics interface. Concretely, we examine a type of noun+verb unit in German, which can be written as one word or two. We argue that the variation in writing is rooted in the units’ ambiguous status in between morphology (one word) and syntax (two words). The major influencing factors are shown to be the semantic relation between the noun and the verb (argument or oblique relation) and the morphosyntactic context. In prototypically nominal contexts, a reinterpretation of the unit as a noun+noun compound is facilitated, which favours spelling as one word, while in prototypically verbal contexts, a syntactic realisation and consequently spelling as two words is preferred. We report the results of two large-scale corpus studies and a controlled production experiment to corroborate our analysis.
