Paleo-Sardinian language

Paleo-Sardinian, also known as Proto-Sardinian or Nuragic, is a set of extinct languages spoken on the Mediterranean island of Sardinia by the ancient Sardinian population during the Nuragic era. Starting from the Roman conquest of Sardinia and Corsica, a process of language shift took place, wherein Latin became the only language spoken by the islanders. Paleo-Sardinian is thought to have left traces in the island's onomastics as well as toponyms, which appear to preserve grammatical suffixes, and a number of words in the modern Sardinian language.

Pre-Indo-European hypothesis

There is toponymic evidence suggesting that the Paleo-Sardinian language may have a connection to the reconstructed Proto-Basque and to the Pre-Indo-European Iberian language of Spain. According to Max Leopold Wagner:
Massimo Pallottino, referring to various authors such as Bertoldi, Terracini and Wagner, highlighted the following similarities between Sardinian, Basque and Iberian:
Archaeologist Giovanni Lilliu hypothesized that the "Basque-Caucasian" idioms of the Bonnanaro culture replaced the previous languages of "pan-Mediterranean" type spoken by the preceding cultures.
Eduardo Blasco Ferrer concluded that the Paleo-Sardinian language developed on the island in the Neolithic as a result of prehistoric migration from the Iberian Peninsula. In his analysis of the Paleo-Sardinian language, he finds only traces of Indo-European influence *ōsa, *debel- and perhaps *mara, *pal-, *nava, *sala which were possibly introduced in the Late Chalcolithic through Liguria. Similarities between Paleo-Sardinian and Ancient Ligurian were also noted by Emidio De Felice. Blasco Ferrer stated:
However, for the linguist and glottologist Giulio Paulis, the Basque language is not helpful in the interpretation of the toponymic heritage of Paleo-Sardinian origin.
Bertoldi and Terracini propose that the common suffix -ara, stressed on the antepenult, was a plural marker, and they indicated a connection to Iberian or to the Paleo-Sicilian languages. Terracini claims a similar connection for the suffixes -ànarV, -ànnarV, -énnarV,and -ònnarV, as in the place name Bonnànnaro. The suffix-ini also seems to be characteristic, as in the place name Barùmini. Infixes -arr-, -err-, -orr-, and -urr- have been claimed to correspond to the North African Numidia, to the Basque-speaking Iberia and Gascony, and to southern Italy.
The non-Latin suffixes -ài, -éi, -òi,and -ùi survive in modern place names based on Latin roots. Terracini sees connections to Berber. Bertoldi sees an Anatolian connection in the endings -ài, -asài. A suffix -aiko is also common in Iberia. The tribal suffix -itani, -etani, as in the Sulcitani, has also been identified as Paleo-Sardinian.
Several linguists, including Bertoldi, Terracini, Wagner, and Hubschmid, proposed various linguistic layers in prehistoric Sardinia. The oldest pan-Mediterranean was widespread in the Iberian Peninsula, France, Italy, Sardinia, and North Africa. The second Hispano-Caucasian would explain the similarities between Basque and Paleo-Sardinian, and the third Ligurian.

Albanian-Balkanic connection

The scholar Alberto Areddu developed the idea that the Shardana, one of the Sea Peoples, were of Illyrian origin. On the basis of various lexical elements unanimously recognized as belonging to the substratum he argued that we must speak for ancient Sardinia and in particular for the most conservative areas of the island, Ogliastra and Barbagia. This particular branch of Indo-European shows strong formal and semantic correspondences with the few testimonies of Illyrian and, with their current linguistic continuation, the Albanian. The concordances are then extended to various toponyms and microtoponyms of the central area. Alberto Areddu provides the following comparisons with the Albanian:

Sardinian	Translation	Albanian	Translation
alase	holly, butcher's broom, weed	halë	bone; remains ; coniferous needle; black pine
laruspinosu	thorny laurel	halëz	arista or remains of the ear; splinter
amadrina	hind	drenje, drenushe	doe
càstia	net to collect straw	kashtë	straw
erba de sos bermes	worm grass	krym	worm
drèddula	ivy	dredhëz	ivy
dròbalu	intestine of pigs	droboli	guts, viscera of all livestock

Etruscan-Nuragic connection

The linguist Massimo Pittau argues that the Paleo-Sardinian language and the Etruscan language were closely linked, as he argues that they were both emanations of the Anatolian branch of Indo-European. According to Pittau, the "Nuragics" were of Lydian origin who imported their Indo-European language to the island, pushing out the Pre-Indo-European languages spoken by the Pre-Nuragic peoples, but this hypothesis does not enjoy consensus. The Etruscan language is believed to be neither Indo-European nor related to the Anatolian languages nor to the Paleo-Sardinian language. The consensus among scholars is that Etruscan is only related to the Rhaetic language spoken in the Alps and to the language attested by a few inscriptions found on the island of Lemnos.
Some examples of Nuragic names of Indo-European origin might be:

calambusa «sprig of cherry tree with fruits», probably Sardian or Nuragic relict , perhaps to compare – not derive – with the Greek «cane, stem».
népide, nébide, nébida, nébidi "fog" ; Sardian or Nuragic relict, to be compared – not derived – with the Greek «fog» .
saurra «humidity of the night, frost, dew», toponyms Saurrecci, Zaurrái, Aurracci, Urracci ; Sardian or Nuragic relict, probably to compare – not derive – with a metathesis, with Lat. ros, roris, Lithuanian rasà, ant. Slavic rose, Vedic «dew» and with the Sanskrit «humidity» and therefore Indo-European..

Some scholars attribute a "Rhaetian-Etruscoid" strand with the suffix -èna that characterizes a series of toponyms in central Italy and in Veneto, passing through Emilia and Romagna. The presence of this suffix is attested, at least since the Middle Ages, also in southern Corsica and in the eastern coast of Sardinia, e.g., Arzachèna, Lugulèna, etc.

Other hypotheses

Archeologist Giovanni Ugas suggested that the three main Nuragic populations may have had separate origins and spoke different languages:

the Balares from the Iberian Peninsula or Southern France and thus of either non-Indo-European or Indo-European origin, linked to the Beaker culture.
The Corsi people from the northeast may be of Ligurian origin.
The Iolaei/Ilienses, who inhabited the southern plains and present-day Barbagia, likely would have spoken a pre-Indo-European language, possibly similar to Minoan and other languages of that area.

The common subdivision of modern Sardinian into the three dialects of Gallurese, Logudorese, and Campidanese might reflect that multilingual substratum. Other Paleo-Sardinian tribes of possible Indo-European stock were the Lucuidonenses from the north of the island, and the Siculensi from the Sarrabus region.
According to Guido Borghi, researcher of glottology and linguistics at the University of Genoa, conclusions appear to display the merits of both Proto-Indo-European and pre-Indo-European/non-Indo-European theories in Sardinian toponyms. Proto-Indo-European appellations can be recognized in Paleo-Sardinian, as in the case of the toponym Thìscali, which could derive from the Proto-Indo-European *Dʱĭhₓ-s-kə̥̥̆ₐ-lĭhₐ with the meaning of "the little in the set of the territories which are in plain sight."