the latter's principles of chain reactions in phonology to inflectional morphology. In Wittmann's view, the basic structure of the sentence is held together by functional items, with the lexical items filling in the blanks. Position in functional space must maintain functional equidistance and disturbances in functional equidistance set off error correcting chain reactions that are cyclical in nature and subject to drift. Thus, functionally salient lexical items will eventually set off a push chain conveyor belt pressure in functional space, sending functionally close-by affixes down the path of attrition. Such is the origin of agglutinating clitics of non-standard oral French from erstwhile lexical pronouns, setting off the attrition of functionally equivalent fusional means of inflection inherited from Old French and Latin: loss of suffixal inflection on the verb, compensated by the rise of proclitic means indicating person, number and tense. Conversely, functional items going down the path of attrition leave behind functional gaps, triggering a drag chain effect on surrounding functionally salient lexical items. Such is the origin of the agglutinating prenominal class markers from erstwhile articles, which are compensated by the rise of postnominal means of expressing definiteness on the noun. With the fulfilment of each cycle of change, a morphologically consistent phonological representation is realized and serves as input to the next cycle of morphological change. Those processes of inflectional renewal have parallels in recent neurolinguistic research, notably in the works by Gabriele Miceli. Wittmann's comparative approach to studying colonial varieties of French from Quebec, the Americas, and the Indian Ocean reveals that the structural gap with written French is inherent in the variety of oral French reflecting the speech of Paris exported from the cities of northern France from the early 17th century onwards. The doubling of DP positions as agreement features and varying degrees of restrictions on verb movement are the only noteworthy developmental features that separate non-creole varieties from creole varieties of French. With his student Robert Fournier, Wittmann debunked within the same theoretical framework the extravagant African-origin hypotheses of Haitian Creole French by Claire Lefebvre and similar farfetched theories. In the end, neither the non-creole koine nor the creole varieties of colonial French turn out to be "creoles" in the sense that creolists would have it. They are both outcomes of "normal" processes of linguistic change and grammaticalization. Wittmann also contributed significantly to the study of other languages, notably languages that are claimed to