Aging and Second Language Acquisition: Differential Success in Learning Latin Grammar Via Implicit and Explicit Feedback

The ability to learn a second language becomes difficult for adults, but not impossible. While implicit processes that can contribute to acquisition of syntax are relatively spared in aging, there are marked deficits in explicit learning, suggesting that language instructions calling on implicit learning might be more effective than that based on explicit learning for older adults. In this experiment, 20 adults ages 66-81 were taught aspects of Latin grammar with either implicit or explicit feedback and were compared to a group of college-age students who previously completed the same task. Overall, the results suggest that the implicit method of teaching the grammar worked better for the older adults but this was not the case for the students. Furthermore, limited exposure to high school Latin markedly increased the ability of older adults to learn the grammar. There were no significant age deficits in learning when only those without previous Latin experience were compared, which bodes well for older adults with strong motivations to learn a second language. Aging and Acquisition of Latin 3 Introduction The critical period hypothesis, first proposed by Penfield and Roberts (1959), suggests that language acquisition becomes significantly impaired if not impossible after a certain age. Since the time the idea was first introduced to neurolinguistics, several researchers have argued over the age at which second language acquisition becomes virtually impossible. Hyltenstam and Abrahamsson (1992) claimed that after the age of 7, people would not be able to attain a nativelike proficiency if their conversations were carefully analyzed. Ellis (1996) and Birdsong (2006) set the age higher, at just before puberty and before the age of 16, respectively. Johnson and Newport (1989) proposed that there are two critical periods with different rates of decline in ability to pick up elements of language. Scovel (1988) proposed that pronunciation is the only aspect of language that is subject to the critical period. Whichever aspect of language is affected, several of these researchers agree that the critical period applies not only to the acquisition of a first language, but also to second language acquisition. While it is evident that adults have more difficulty in acquiring a second language, the critical period hypothesis has been nearly dismissed by researchers. Instead, most current research adopts the idea that the ability to learn a second language decreases steadily with increasing age. Hakuta and Bialystok (2003) used 1990 census data to disprove the idea of the critical period hypothesis in second language acquisition. In their study, they examined native Chinese and Spanish speakers who moved to the United States. By including factors such as age of immigration and level of education, they were able to create a regression that represented level of language acquisition versus age. In their study, Hakuta and Bialystok looked at data from people ages 10-70 who had been in the United States for at least 10 years. If a critical period in second language acquisition does exist, the slope of the regression would be markedly different Aging and Acquisition of Latin 4 before and after the proposed critical age range. Instead of finding a plateau characteristic of a critical period, they found a negative linear relationship between age and the ability to learn a second language. Several researchers have agreed that there is a linear decline in the ability to learn a second language with age instead of a critical period (Singleton 2001, Midford and Kirsner 2005, Hyltenstam and Abrahamsson 2000, Birdsong 2006). Several studies have examined the effect of age of arrival in a new country (and subsequent age of acquisition) on a person’s ability to pick up the language of that country. Birdsong (2006) noted that there is a negative correlation between age of arrival and ultimate attainment of a second language. He also found that later ages of arrival often led to more errors in grammatical judgment and a higher degree of a non-native accent. Flege and Yeni-Komshiam (1999) examined native Korean speakers trying to learn English and also found that the strength of their foreign accent was positively correlated with the age of arrival in a new country. In addition, they used a grammatical judgment task to assess the morphosyntax of the Korean speakers and found that the degree of native-like morphosyntax was negatively correlated with the age of arrival in America. Adults can attain a native-like proficiency in a foreign language Several studies suggest that with significant exposure, adults can approach native-like proficiency in a second language. Marinova-Todd (2003) tested 30 adults who arrived in an English-speaking country after the age of 16 and who had been living in an English-speaking country for at least 5 years. Participants were tested on nine measures including pronunciation, spontaneous speech, read alouds, morphosyntactic accuracy, lexicon, and narrative language. In the study, 3 subjects were indistinguishable from native speakers on all 9 measures and an additional 6 subjects were indistinguishable from native speakers on 7 measures. Birdsong Aging and Acquisition of Latin 5 (1992) examined 20 English speakers with an average age of 40 who were first exposed to French after puberty and found that 15 of them reached native-like abilities in grammar judgment with significant exposure to the language. Bongaerts et al. (2000) studied advanced late learners of Dutch and found that adults (with a mean age of 40) could demonstrate a native-like accent with enough opportunity to practice the language. These studies prove that while learning a second language may be more difficult at an older age, it is not necessarily impossible. Rossi et al. (2006) examined event related potentials in late learners (19-40 years of age) of a second language to compare their neural experience of a language to native speakers. Nonnative subjects were exposed to tasks in German and Italian that had word category violations and morphosyntactic agreement violations and their responses were compared to native speakers. High proficiency late learners of German and Italian had the same ERPs as native speakers during the task, whereas low proficiency late learners had ERPs that were significantly different from native speakers. The results suggest that it might be the level of proficiency in a second language, not age of acquisition, that accounts for the differences between late learners and native speakers. This study also showed that late learners of a second language could be proficient to the level where their neural processing of the second language is the same as native speakers. Different aspects of language are processed in different brain regions Ullman (2001) examined the declarative-procedural model as it relates to languages. Through brain imaging and looking at the differences between Alzheimer’s and Parkinson’s disease along with the differences between anterior and posterior aphasias, he was able to show that syntax is processed mainly in the frontal cortex and basal ganglia whereas lexicon is a function of the medial-temporal lobe, particularly the hippocampus. Birdsong (2006) noted that Aging and Acquisition of Latin 6 while episodic memory, associative memory, and semantic memory show marked age deficits, there are fewer declines in procedural memory throughout the lifetime. Therefore, the ability to process grammar while learning a second language may be relatively spared in aging. The learning of vocabulary, however, may prove more difficult due to the declines in associative and semantic memory. Individual differences and their effects on distinct language processes While general factors related to aging may contribute the most to the difficulties in learning a second language throughout one’s lifetime, individual differences also play a role. McGeorge and Crawford (1997) looked at psychometric intelligence and its effects on series completion, grammar completion, and other tasks that are related to learning a second language. Overall, scores on the WAIS were less related to implicit tasks than to explicit tasks. This suggests that the greatest variability among late language learners may arise in the area of lexicon rather than grammar. Gebauer and Mackintosh (2007) supported the notion that abilities in implicit learning are not dependent upon the level of psychometric intelligence. Using Reber’s (1967) artificial grammar task, a serial learning task, and a process control task, the researchers showed that when subjects received implicit instructions on the tasks, their performance was not correlated to measures of psychometric intelligence. Bley-Vroman (1990) proposed a hypothesis for why success in second language acquisition has more variability than in first language acquisition. While people learning a first language have access to universal grammar—the innate ability to pick up on common regularities and principles of grammar that is equal among individuals, late learners of a second Aging and Acquisition of Latin 7 language are without this tool and success is more closely tied to cognitive differences between individuals. This theory became known as the Fundamental Differences Hypothesis. Age-related cognitive factors and second language acquisition There are several factors that could contribute to the difficulty in learning a second language with increasing age. Park (2000) suggests that the three main deficits that occur with cognitive aging are decreases in working memory, processing speed, and inhibitory control. Decreased suppression makes it more difficult to think in the second language instead of relying on one’s first language. If these factors do influence second language acquisition, there will be a lot of variability in older peoples’ ability to learn a second language because there is a wide range i