Looking back is all we can do in a world difficult to analyze.
Ancient tribes give more answers than current ones, be it ancient Hebrews, Proto Basques or in this case, the ancient Sardinian civilizations.
Apparently their language was the only one in Europe somewhat related to the Basque language.
More recently, Sardinia was claimed by the Greeks and the Phoenecians, the Romans and Carthaginians, the Vandals and Ostrogoths. The rich history of their unique language, perhaps the only one in Europe related to proto-Basque, and their genetic lineages that preserve Western European Farmer ancestry thousands of years after the rest of Europe had been influenced by Steppe haplogroups, make the modern Sards some of the most ancient people we know.
Source: YouTube
Sardinian DNA | Genetically Unique People in Europe – YouTube
So eg. sakkáyu, -a, sakkaggu, -a is in Sardinian a lamb or a goat of a year or a year and a half; brings to mind the Aragonese segalo, Catalan sugali, Béarnese sigàlo «goat of the same age», which my colleague Rohlfs combined with the Basque seguila «chèvre d’un an» which seems to be derived from the Basque seliail, segai! «svelte», safaildu «décharner, maigrir». Of course, not everything is equally certain, and the investigation must be continued and expanded. Naturally I am far from wanting to identify Sardinians and Basques, Sardinians and Iberians, I believe that one must always bear in mind that other influences may also have manifested themselves, long-standing Mediterranean influences, Ligurian and perhaps even Alpine influences. Certain coincidences between Sardinian and Albanian are also notable”
Max Leopold Wagner, Osservazioni sui sostrati etnico-linguistici sardi, 1933