This paper demonstrates that, within substratal research, prior to undertaking any comparative endeavour, it is necessary to conduct a thorough distributional analysis of the morphological regularities displayed by the language under consideration, so as to determine the phonological rules governing diachronic changes, which leads to establishing the typology of the substratal language. The application of this rigorous methodology to Palaeo-Sardinian toponymic material makes it possible to recognize the primitive agglutinative typology, and thereby to precise its relation to Palaeo-Basque. After having highlighted some flaws and weaknesses of prior reconstructions, the author first describes the benefits stemming from a systematic segmentat...