Throughout this work, I have argued that multiple factors, in combination with one another, may account for age effects to a statistically significant degree. Age of exposure, like length of residence, may give us little indication of the underlying mechanisms responsible for attainment; instead, depending on the individual case, it may be more of an indication of cumulative experience, including constraints on the language learning process from several fronts. Those initiating language acquisition after puberty may be subject to an especially complex combination of influences from social, psychological and cognitive realms.

Putting Age Effects in Context

Clearly, age of exposure is but one factor in ultimate attainment, and not an especially informative one if we consider the results gleaned from Chapters 3 and 4. To isolate the significance of age from its socio-cultural and psychological context is to misconstrue its impact. Critical-period studies have typically done just this, with too little attempt to clarify the nature of its influence. In effect, the absence of focus on individual factors has done little to advance a real understanding of the process. Furthermore, while quantitative analysis has been a valuable tool for verifying factor relationships, it has brought us only so far. How do various aspects of experience operate in practice? How do shifts in their balance over time affect long-term outcomes? These questions cannot be answered through discrete measures alone, much less with an exclusive emphasis on group performance. The individual's perspective must be explored if we are to understand the roles played by these critical factors.

Through an integrated methodology, appropriately measuring the impact of age relative to its concomitant influences is possible. We must discover how the late learner builds L2 experience that reflects his or her personal needs, desires, and styles – cognitively, socially and psychologically speaking. By merging psycholinguistic and sociolinguistic approaches, we may understand how some learners continue on, past predicted stages of non-native-ness. In so doing, the balance of relevant universal and individual influences also becomes clearer.