Previous accounts of preverbal subjects in Spanish and European Portuguese (EP) in the literature have debated the syntactic position of these elements. According to some analyses, preverbal subjects are canonical arguments appearing in an A-position (e.g. Goodall 2001, 2002; Suñer 2003 for Spanish; Duarte 1997; Costa 2004 for EP). Other analyses propose that preverbal subjects are non-arguments appearing in a left-peripheral - perhaps CLLD - A'-position (e.g. Uribe-Etxebarria 1990, 1995; Ordóñez & Treviño 1999 for Spanish; Barbosa 1996, 2000 for EP). Although Galician is an ideal language for insight on this debate due to linguistic ties with EP and political ties with Spain, Gupton (2006) obtained inconclusive results regarding the status of preverbal subjects in Galician. As the literature on Galician lacks descriptions of preferred word orders according to discourse context, I collected quantitative and qualitative experimental data to describe the syntax-information structure interface in Galician. The vast majority of speakers of this minority language are Spanish-Galician bilinguals with (self-reported) high levels of competency in both languages. This is of relevance because a variety of bilinguals, including heritage speakers, attrited L1 speakers, and those who have been claimed to have incompletely acquired the heritage language have been shown to exhibit instability and optionality at the linguistic interfaces, in particular at the syntax-discourse pragmatics interface (e.g. Hulk & Müller 2000; Sorace 2005 among numerous others), which is the subject of investigation in this dissertation. The data collected indicate a marked preference for SVO in a wide variety of discourse contexts, a preference that differs from those claimed to apply in similar contexts in Spanish (e.g. Ordóñez 1997, Zubizarreta 1998, Casielles 2004). Assuming that the presence of clitics implies the projection of f (Raposo & Uriagereka 2005) and the extension of the preverbal field into the left periphery, the cliticization data gathered for Galician in main clauses, subordinate clauses and recomplementation contexts suggest a number of preverbal positions in which preverbal subjects, affective phrases, and Topic elements may appear, one of which I suggest is Spec, DoubledFceP, following Martín-González (2002), but with proposed modifications. The data also suggest necessary modifications for López's (2009) syntax-information structure interface proposal in Romance, which suggests a reduced, syncretic left-peripheral position (Spec, FinP) in which CLLD Topics, wh- elements, and Fronted Focus elements appear and are assigned [+c] (contrastive) by the Pragmatics module. Within the preverbal architecture I propose, preverbal subjects and other left-peripheral elements coincide, but in a variety of syntactic positions. Therefore, for pragmatic feature assignment to successfully assign [+c], Pragmatics must distinguish between preverbal subjects and other left-peripheral phrases.