The methods of comparative linguistics can be fruitfully complemented by typological research. As the reconstructed state is expected to find a place in the typology, the latter research can help us select among the historical approaches. However, it is crucial that the typological research is not based on certain, often implicit assumptions on the relation between phonetics and phonology, perhaps even more so in the case of coronal places of articulation, which are the focus of the thesis. The typology of the coronal places is used to critically evaluate two approaches to the development of palatals in Indo-Iranian, Lipp (2009) and Repanšek (2019), which both stipulate intermediate states contrary to the established typology. The new approach towards this development presented here does not suffer from this problem and also suggests the reintepretation of pie. /s/ as [s̱] along the lines of Vijūnas (2010), allowing us to establishe a link between the satem sound change of affricatization and the RUKI sound rule, which had already previously been linked to the retracted interpretation of *s in the proto-language (eg. Bičovský 2008).