Do subcortical structures control 'language selection' in polyglots? Evidence from pathological language mixing

In the field of multilinguism, 'switching' defines a mechanism operating automatically when speakers shift among different languages. While the neural basis of this mechanism is unknown, recent studies of polyglot aphasia have suggested a possible role of subcortical structures. We report a case of subcortical polyglot aphasia which provides further evidence for a role of the basal ganglia in the switching mechanism. A polyglot female (Armenian-English-Italian), after a subcortical infarction in the language dominant hemisphere, developed a non-fluent aphasia characterized by pathological mixing among these languages in oral production tasks. This case confirms that damage to subcortical structures may result in different types of dysfunction in the mechanisms implicated in the selection of languages.