This chapter illustrates grammatical changes in German heritage varieties through an in-depth analysis of the three exemplary settings of German-speaking enclaves: Barossa German in Australia, Volga German in Russia and Blumenau German in Brazil. It provides a model study for investigating heritage languages by including both cross-linguistic and intergenerational data. Analyzing spoken data from two and in one case three) different generations, it is demonstrated that the reduction of case marking in the noun-phrase follows an identical path in all settings despite the typological difference of the replica language. This is explained as an internal development process of the heritage language, which is accelerated in the contact situation. In contrast, the pronominal system undergoes a different restructuring process in all three communities, which is interpreted as individual development in the respective contact settings. The detailed in-depth-analysis demonstrates that different processes are at work: phonological processes (such as assimilation processes), cognitive processes (accusative constructions extending their meaning to dative constructions), and linguistic economy (article omission). Only in the case of article omission, language contact comes in where the German contact varieties replicate a construction of the replica language.