Analyzing free variation with harmony – A case study of verb-cluster serialization

In German, a verb selected by another verb normally precedes the selecting verb. Modal verbs in the perfect tense provide an exception to this generalization because they require the perfective auxiliary to occur in cluster-initial position according to prescriptive grammars. Bader and Schmid (2009b) have shown, however, that native speakers accept the auxiliary in all positions except the cluster-final one. Experimental results as well as corpus data indicate that verb cluster serialization is a case of free variation. I discuss how this variation can be accounted for, focusing on two mismatches between acceptability and frequency: First, slight acceptability advantages can turn into strong frequency advantages. Second, syntactic variants with basically zero frequency can still vary substantially in acceptability. These mismatches remain unaccounted for if acceptability is related to frequency on the level of whole sentence structures, as in Stochastic OT (Boersma and Hayes2001). However, when the acceptability-frequency relationship is modeled on the level of individual weighted constraints, using harmony as link (see Pater2009, for different harmony based frameworks), the two mismatches follow given appropriate linking assumptions.