Bilingualism, Aging, and Instructional Conditions in Non-Primary Language Development

Abstract

A central question in second language acquisition (SLA) is the interaction of internal and external variables, and this dissertation contributes to the field by investigating the effects of bilingualism and aging on language development under different instructional conditions. Prior research suggests that bilingual young adults generally have an advantage over monolinguals in learning a non-primary language (e.g., Cenoz & Valencia, 1994; Sanz, 2000, 2007), an advantage that is more evident in less explicit instructional conditions (e.g., Lado, 2008; Lin, 2009). In addition, research suggests that older adults are better able to learn non-primary languages under less explicit than explicit conditions (Midford & Kirsner, 2005; Lenet et al., 2011). To aid in explaining the role of bilingualism, aging, and instructional conditions on development, this study also measures attentional control (ANT and Simon task), language aptitude (MLAT), and non-linguistic implicit sequence learning (ASRT).

Ninety-four participants who were either young adults (age 18-27) or older adults (age 60+) and either monolingual English speakers or bilingual English/Spanish speakers completed the Latin Project (Sanz, Stafford, & Bowden), targeting the assignment of thematic roles to nouns in Latin, which differs in cues from that of English or Spanish. Participants completed a vocabulary lesson and quiz, a battery of four assessments as pre, immediate post, and delayed posttests, and task-essential practice either with or without previous grammar explanation (more and less explicit instruction). Language development was measured via accuracy and reaction time. Results revealed a bilingual advantage in accuracy, largely due to increased aptitude compared to monolinguals, and especially for bilinguals in the more explicit condition, a finding that differs from studies that used metalinguistic feedback as explicit instruction (e.g., Lado, 2008). In addition, older adults' accuracy did not vary by condition, suggesting that grammar explanations prior to practice are not as disruptive as is metalinguistic feedback (Lenet et al., 2011), nor did it generally differ from young adults' accuracy. Attentional control and non-linguistic implicit sequence learning predicted changes in latency rather than accuracy. These findings add to our understanding of bilingual effects on cognition, mitigate negative stereotypes of aging and learning, and have implications for foreign language pedagogy.