The Primary Progressive Aphasias (PPA) are a collection of clinical syndromes caused by early-onset neurodegenerative disorders that affect specific speech and language networks in the brain. In this talk, I will describe the cognitive, neuroimaging and neuropathological features of this disorder. I will demonstrate how a cognitive neuroscience approach to the study of PPA has improved not only clinical care but also understanding of the neurobiology of language. Finally, I will discuss a possible link between neurodevelopmental disorders and advancing age focal neurodegeneration, highlighting the need for a lifespan approach.