Language, meaning, and localization Last year's words, next year's words

Neurologic practice is deeply rooted in the ideal of localization. Some would argue that neurology arose in the mid-18th century from the study of language localization, regarded as a uniquely human function. The classic aphasias, those described by Broca and Wernicke, were believed to represent exemplars of lesion-symptom mapping, but many features of language-onset dementias went unexplained by conventional aphasiology.² The description of aphasia syndromes in neurodegenerative diseases has largely overturned the static conceptualization of a brain language postcode.³ While incremental and cumulative, these neural network–based conceptual changes have proven critical for elucidating the neural basis of communication, both in healthy speakers and those with neurologic disease. Greater understanding of the interconnectedness and functionality of language regions remains particularly important clinically, such as for decision-making around epilepsy or oncology surgery, and can assist in providing prognostic information for affected individuals and their families.