Those who work with older people frequently report that people who have learned a second language appear to lose facility in that language as they age. This phenomenon has also been observed by the friends and relatives of those older persons who have learned more than one language. However, there is very little research investigating changes in second (or other) languages across the lifespan. In contrast, extensive research exploring first language change in ageing has provided ample evidence of patterns of change in first language abilities across the lifespan. There is also much research linking these patterns to age-related cognitive change. The question addressed in the first study of this project was whether patterns of age-related change in second language abilities are similar to patterns of change in first language abilities. The performance of English first language and English second language (Chinese first language) participants aged 20 to 79 was compared on four language ability tasks. Information relating to language background, language use, and education was also collected. In general, the patterns of first and second language change across the lifespan were similar with facility in one ability, verbal fluency, decreasing with increased age. Background variables were also found to affect second language ability within the English second language group. The second study investigated whether those processes associated with age-related cognitive decline, and therefore age-related changes in first language, also influence changes in second language verbal fluency in ageing. English second language (Chinese first language) participants aged 20 to 79 performed a number of tasks designed to measure the cognitive constructs of speed of processing, inhibitory efficiency, and working memory capacity. The effect of age on verbal fluency in second language was mediated by speed of processing. There was no evidence of reduced inhibitory efficiency with increased age. Scores from the working memory capacity tasks could not be analysed due to the involuntary and unexpected intrusion of their Chinese language for some bilingual participants. The results were interpreted in terms of fluid and crystallised intelligence, and also the differences in bilingual compared to monolingual language processing. Implications for testing and assessment of individuals in their non-native language are discussed, and both the limitations of the research and also possible future research directions are identified.
|Qualification||Doctor of Philosophy|
|Publication status||Unpublished - 2007|