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.

Two approaches to developing a theoretical platform for the study of sociosyntax are compared. The first approach adopts a sentence-based theory of syntax and an objectivist theory of semantics, which serves to qualify forms as variants of a sociolinguistic variable. The second approach replaces the sentence with the sign (signaled by grammatical formatives and word-order patterns) as the primary organizing principle of grammar and the basic carrier of meaning. It also replaces objectivist semantics with subjectivist-construal, functional-semiotic semantics under which grammatical meanings offer particular speaker perspectives. In this second approach the alternants of interest to sociolinguists are in almost every case different in their component meanings, yet amenable to conceptualization as variants of a sociolinguistic variable. Variation is seen as resulting from pressures exerted simultaneously by the exigencies of communication and the force of both internal and external sociolinguistic factors. This approach offers considerable advantages for the study of sociosyntax, advantages that pertain to both overall theoretical coherence and clearer paths to the explanation of the effects of predictor variables. We illustrate these advantages with analyses that demonstrate the impact of switch-reference on the presence and absence of Spanish yo, tú, ella, él, etc. ('I, you, she, he').