Tests Empirical and Comparative for the Hypothesis of an Eurasian Palatal Change in Basque

This article formulates and applies a reproducible, multi -level methodology to test thehypothesis that a subset of Basque lexemes beginning in s - derive from pre -Basque initials k/gthat underwent assibilation (k → g → s). The method combines exhaustive internal invento-rying (dialectal and medieval attestations), morphological reconstruction (CVC pre-Basquetemplates and known internal sound laws), strict inter -family comparison across relevantEurasian families, toponymic evidence, and statistical controls against accidental convergenceand borrowing.