Age-grading—a cornerstone of sociolinguistic theorizing—is hypothesized to follow a U-shaped pattern. Vernacular forms peak in adolescence, abate in middle age, and increase again in retirement, forming a vernacular tail. A complete understanding of age-grading has been hampered by a lack of empirical evidence across the entire adult trajectory and a relatively narrow understanding of speakers’ motivations to change. This paper presents data from a dynamic panel dataset of Tyneside English speakers, covering successive cohorts over the entire adult lifespan. An analysis of (ing) reveals that the U-shaped curve is occupationally niched; only professional educators demonstrate clear retrenchment followed by a tail. Drawing on educational policy research, we argue this effect is largely driven by institutional (and heavily policed) expectations of UK educational policies. We are the first to demonstrate the occupationally niched nature of the U-shaped curve and provide quantitative evidence of the effect of educational policy on linguistic production.

Subject dislocation (SD) is common across languages. In French, it is a vernacular norm. In English, it is comparatively rare. This article examines English SD in a unique contrastive situation in Ontario, Canada: two communities where SD is a community norm, one where individuals speak both English and French (Kapuskasing), and the other where the population speaks English only (Parry Sound). Dislocated subjects are produced by the same underlying linguistic mechanisms in both places, with parallel constraints by type of subject and intervening material, suggesting a typological universal. However, SD is age-graded in Kapuskasing, regardless of heritage language. In Parry Sound, it is obsolescent, in steady decline over the twentieth century. We conclude that while typological trends are underlain by universal cognitive processes, locally embedded sociocultural influences are the source of differentiation.

In an area of holoendemic malaria in Northern Tanzania, Anopheles gambiae s.l. females were age-graded by Polovodova's method and dissected for sporozoites. Age-specific sporozoite rates implied that mosquitoes acquired new infections at all ages. The extrinsic period lasted just over 3 gonotrophic cycles (9–11 days). Very high sporozoite rates in the oldest females implied the absence or rarity of genetic refractoriness to infection. A method is described for estimating the proportion of bloodmeals which result in mosquito infection. This method makes relatively few assumptions about mosquito behaviour, and could be useful for evaluating transmission-blocking interventions. Overall, it is estimated that about 21% of meals are infectious. This is much higher than previous estimates derived either from experimental mosquito feeding studies or from similar age-grading data collected from the same area in 1962. Various alternative explanations are considered, and it is concluded that there has been a 2.5-fold increase in human infectiousness in the last 25 years. This is partly attributable to suppression of human infectiousness by widespread chloroquine usage during the 1960s, followed by removal of this effect by drug resistance. It is argued that chloroquine would be expected to select for increased infectivity in the parasite, and this may also have contributed to the observed increase.