Primary progressive aphasia is a clinical syndrome defined as a progressive isolated speech or language disorder. The heterogeneity of its clinical presentation reflects different patterns of focal brain atrophy. However, the correspondence between the clinical/anatomical features and pathological findings is still unclear. I will present longitudinal neuroimaging analyses and initial pathological findings of the UCSF patient population. Regardless of the underlying pathological processes, focal neurodegenerative diseases are a powerful model to study the organization of language processes in the brain. I will present cognitive and neuroimaging studies focusing on the organization of categorical knowledge, syntactic comprehension and auditory short-term memory in PPA and other focal neurodegenerative diseases.