The introduction to this volume sums up and discusses some of the issues fundamental to the study of syntactic variation, such as the problem of semantic equivalence (since syntactic variants often have different meanings), the delimitation of syntactic alternations, the relation between linguistic and social conditioning of syntactic variables, and the explanatory frameworks that are proposed in the chapters to account for the linguistic choices speakers make when employing syntactic alternants.

This chapter argues that it will make results of variationist studies more relevant for linguistic theory if internal predictors assumed to constrain syntactic variation are operationalized in a way that explicitly relates them to semantic or – more broadly – functional hypotheses. We use word order in Danish adverbial subordinate clauses as a case study for how a hypothesized semantic difference between variants can be operationalized. This word order alternation concerns the relative placement of sentential adverbials and finite verbs in subclauses. While the variable is structurally well defined (Adverb < Verb vs. Verb > Adverb), it challenges classic theoretical and methodological ass+L13umptions in variationist studies by entailing a semantic difference, since the two word orders convey subtly different meanings when used in subclauses. For this study, we operationalize a set of linguistic predictors related to the two most prevalent meaning hypotheses given in the literature, the assertivity and the foregrounding hypothesis. Mixed-effect models and random forest analyses are used to examine the effects and strength of intra- and extralinguistic (social) predictors. Geographical differences related to social stratification indicate an ongoing standardization process emanating from the capital of Copenhagen. The import of our findings related to linguistic theory is discussed.