Child speech is highly variable. The speech apparatus--the vocal tract, tongue, teeth, and vocal folds--develop at different rates for different children, which helps explain some of the variability in children's speech. For example, the ratio of the oral to pharyngeal cavities changes as children age, making it difficult to establish reliable…

Within discourses of language endangerment, life stages such as child language acquisition, adolescent language shift, and the death of community elders figure prominently, but what of the role of other, intermediate life stages during adulthood and professional life in the course of language obsolescence or revitalization? Drawing from long-term…