ABSTRACT
This chapter focuses on biological, clinical, and social thresholds and significant life events that potentially impact L2 development across the lifespan. It begins with a discussion of the debate around the question of whether there is an age-bounded critical or sensitive period for L2 acquisition at some point in life and indeed whether there is a multiplicity of such periods. This is followed by a discussion of clinical thresholds through focusing on cognitive and brain reserve theories that have suggested that the reason why certain individuals are less susceptible to disruption in their cognitive functioning might have to do with the fact that some individuals have a larger cognitive reserve (biologically and functionally) than others. Finally, the last focus is on retirement as a socially determined and linguistically constructed concept altering the process of cognitive aging and language acquisition, use, and attrition. In order to identify dis/continuity patterns of the entire linguistic spectrum as well as cognitive functioning across retirement, we bring together a range of perspectives regarding (a) original research agendas and (b) innovative methodological approaches, notably from the fields of second language acquisition, psycho-, socio-, and neurolinguistics.
