The chapter presents two fundamentally different model-theoretical assumptions on the functional neuroanatomy of cognitive processes, which are based on a more localistic view or a more holistic view of brain function. In contrast to sensory-motor processing, higher cognitive abilities, such as aspects of language processing, cannot be assigned to narrowly defined brain areas over a longer period of time, even with intracranial recordings. It is shown that cognitive processes are rather the result of neuronal networks working together only temporarily, whose electrical activity can be assigned to the alpha, beta, gamma, epsilon or ripple frequency bands, for example. The neurophysiological principles of such short-term oscillatory cooperations are presented and explained using examples of different sub-performances of language processing. This is followed by a discussion of findings from non-invasive electrical stimulation (tACS/tDCS), which can be used to influence the brain electrical activity of certain brain areas for therapeutic work with language-impaired patients.