 At that time morphology, phonology and morphonology were also of interest to him.Since 1972, what was later called 'sociophonology' has been developed, first as 'fast speech rules', later in a refined model on 'casual speech' and competing phonological processes and rules.From 1973 onwards, in search of 'external evidence' for linguistic theoretical assumptions (as opposed to generative models, but as an important science-theoretical background for theoretical arguments), Dressler became interested in the disturbed speech of aphasia.