This survey aims at describing and analysing onsets and codas – with special focus on consonant clusters – of selected Germanic and Romance varieties spoken in the language contact area of Trentino-Alto Adige/Südtirol. We will try to determine a) what dialects can reveal about syllable theory and the universality of the sonority scale and b) whether varieties which are in contact influence one another so as to allow for similar clusters. The corresponding standard varieties (Standard German and Standard Italian) will be taken as a reference in order to identify which similarities and, more importantly, which differences the dialects under investigation exhibit with respect to them. The collected data will reveal that, generally, the examined Germanic and Romance dialects conform to the sonority scale proposed for Standard German and Standard Italian, respectively – the only exception being found in the case of Tyrolean. It will also emerge that the investigated Germanic and Romance dialects behave differently with respect to the grammar of consonant clusters. Dialects turn out to be generally more permissive than their correspondent standard varieties since they allow for lower thresholds under which their clusters are considered as illicit in sonority-related terms. Furthermore, differences will be identified within the various Germanic and Romance dialects. Indeed, it will be shown that, on the one hand, the same grammar is shared by some varieties of the Germanic group and by some varieties of the Romance group. On the other hand, other varieties will prove to be more stringent and will display their own grammar.