SummaryIn this thesis I compared Russian and Norwegian patients with Alzheimer’s disease (AD) and verbal morphology in these two groups of informants. Norwegian is a language with a relatively simple verbal morphology, but a little more complex than English. Russian has a verbal morphology far more complex than both English and Norwegian. We know that AD patients have word finding problems. I wanted to find out if it is possible that they also have problems with verbal morphology. Earlier studies shows that it does not seem as English and Norwegian AD patients have particular problems with verb inflection. Is it possible that this is due to the simple verbal morphological systems and not because this ability is well preserved? The answer to this question seems to be, yes, for AD patients the complexity of the verbal system in their first language influences their ability to inflect verbs. High type frequency of verb classes as well as clear phonological cues or markers are important for AD patients when they inflect verbs. This finding is in accordance with a cognitivistic view on language.