Task complexity has attracted the attention of researchers interested in syllabus design and language pedagogy since the eighties. A scarcely investigated feature is storyline complexity, and its effects on complexity, accuracy and fluency (CAF) in narrative writing. This study examines the effects of storyline complexity in the narratives of 60 low to upper-intermediate Swedish secondary school learners of Spanish as a foreign language. Furthermore, the study addresses the role of proficiency in mediating these effects, as it sets out to ascertain whether storyline complexity affects different dimensions of CAF performance to the same extent at different proficiency levels. To elicit data, two narrative tasks were used. Both of them had a loose structure but differed in their storyline complexity, with the simple task having a single storyline and the complex task a dual storyline. In turn, to assess the learners’ proficiency level, a multiple-choice test was employed. The study used a between-subjects design, and the statistical treatment relied on a two-way analysis of variance (2 storyline complexity conditions x 2 proficiency levels). Complexity and fluency turned out to be higher in the complex condition irrespective of proficiency, whereas mixed results were found for accuracy at different proficiency levels.

Research on task complexity focuses on the influence of different task features on language learners' production in terms of linguistic complexity, accuracy, fluency and lexis. Within this field, a line of investigation that has attracted much attention is the influence of resource-directing and resource-dispersing features of cognitive task complexity. Notwithstanding, the evidence assembled to date has yielded contradictory results that are not consistent across task type, proficiency level, and task modality. The study attempts to shed some light by examining the role of task complexity along the [± Here-and-Now] dimension in written production, and whether the effects of task complexity are the same at different proficiency levels. To this aim, data were elicited from Swedish high school learners of Spanish as a FL (n = 67) using two different versions of a narrative task. In turn, the participants' proficiency was assessed using a multiple-choice test. The results suggest that task complexity had a statistically significant effect on the four areas of language production. On the other hand, when splitting the sample into proficiency groups, differences across task conditions were found, but only in the higher proficiency group. These results are interpreted in light of Robinson's Cognition Hypothesis and Skehan's Trade-Off Model.

One of the least understood (and also least investigated) factors conditioning interlanguage transfer from a prior non-native language (L2) to a subsequent non-native language (L3) is proficiency in the source language of influence. The present study examined whether L2 German syntactic proficiency, defined here as level of development in a cluster of structural properties related to verb placement, had any effect on the occurrence of interlanguage transfer in the L3 English. More specifically, the research question guiding the study asked whether mastery of these properties (discontinuous verb placement, verb final and inversion) constrained the timing, extent and type of such transfer. The corpus analyzed comprised L2 and L3 data from Spanish\slash Catalan bilingual learners (n = 238) aged 9--13. A series of ANCOVAs were run on the data, keeping constant various measures of L2 syntactic proficiency and controlling for L3 overall proficiency and biological age as covariates. The results of these tests yielded a significant effect for verb final (p = 0.046) and subject-verb inversion (p = 0.002). Furthermore, an inverse relationship was found between L2 syntactic proficiency and interlanguage transfer, in that low L2 proficiency in the use of verb final and (especially) inversion was associated with an overgeneralization of discontinuous verb placement in embedded clauses in the L3.

This chapter conceptualizes and discusses two subtypes of multilingualism, namely, (a) third language acquisition in learners who have prior experience in acquiring one or more non-native languages, and (b) subsequent language acquisition in learners who are bilingual from an early age. The chapter also discusses the roles played by age (both biological age and age of onset) and proficiency in multilingual acquisition. As regards age, the discussion focuses primarily on two aspects, namely, differential effects in instructed and naturalistic contexts, and the apparent superiority of older learners and late starters against younger learners and early starters. It is stressed that further research is necessary in order to identify and single out the particularities of L3 acquisition for learners with prior experience in the concurrent or consecutive learning of one or more non-native languages. Likewise, the chapter highlights the need to obtain a deeper understanding of how age-related differences in the level of linguistic entrenchment in multilinguals constrain L3 learning after exposure to additional languages. With respect to the proficiency factor, it is argued that it is important to consider proficiency thresholds and to tease apart the distinctive effects of proficiency in the target language (the L3) and in the background languages when exploring linguistic development among multilinguals. These distinctive effects are also relevant for understanding crosslinguistic influence in L3 acquisition, above all in determining the potential source languages and the direction of this influence.