There is general agreement that the core area of Tartessos is around Huelva extending to the valley of the Guadalquivir, while the area under Tartessian influence is much wider
The Tartessian language is the extinct Paleohispanic language of inscriptions in the Southwestern script found in the southwest of the Iberian Peninsula mainly in the south of Portugal ( Algarve and southern Alentejo), but also in Spain (south of Extramadura and western Andalusia). There are 95 of these inscriptions with the longest having 82 readable signs. Around one-third of them have been found in Early Iron Age necropolises or other Iron Age burial sites associated with rich complex burials. It is usual to date them from the 7th century BC and consider the southwestern script to be the most ancient paleohispanic script with characters most closely resembling specific Phoenician letter forms found in inscriptions dated to c.825 BC.
Tartessian is usually treated as unclassified (Correa 2009, Rodríquez Ramos 2002, de Hoz 2010) though several researchers have tried to relate Tartessian with known families of languages. Koch (2010 and 2011) claims that much of the Tartessian corpus can be interpreted as Celtic, with forms possibly of sufficient density to support the conclusion that Tartessian was a Celtic language, rather than a non-Celtic language containing a relatively small proportion of Celtic names and loanwords .A critical view of Koch’s work that considers it is not really convincing and that points out inconsistencies, in form and content, and ad hoc solutions, but recognizes that a strong vote for the Celtic hypothesis by Celtic nationalists can be found at Bryn Mawr Classical Review 2011.09.57.
The Turdetani of the Roman period are generally considered the heirs of the Tartessian culture. Strabo mentions that “The Turdetanians are ranked as the wisest of the Iberians; and they make use of an alphabet, and possess records of their ancient history, poems, and laws written in verse that are six thousand years old, as they assert.” It is not known when Tartessian ceased to be spoken, but Strabo (writing c. 7 BC) records that “The Turdetanians … and particularly those that live about the Baetis, have completely changed over to the Roman mode of life, not even remembering their own language any more.”
The legendary Ninth Legion, Legio IX Hispana, the Spanish Legion, was one of the oldest and most feared units in the Roman Army. Put together in Spain by Pompey in 65 BC, it came under the command of Julius Caesar who was Governor of Further Spain in 61 BC, and served in Gaul throughout the Gallic Wars from 58 – 51 BC, the Legion was decisive in ensuring Caesar’s control of the Republic.
After Caesar’s assassination it remained loyal to his successor Octavian. It fought with distinction against the Cantabrians in Spain from 25 – 13 BC but suffered terribly in the British revolt led by Boadicea ( Boudica) in 60AD, losing as many as 50 – 80 per cent of its men . However, several high ranking Officers who could only have served after 117 AD are well known to us, so we can safely assume that the core of the Legion was still extant in the reign of Hadrian, 117 – 138 AD.
The first great leader of the Feni (later “Gaels”) in Ireland, Tuathal (Teuto–valos) Techtmar, was probably a Roman soldier, commanding Q-Celtic speaking auxiliaries from Spain. The earliest known source for the story of Tuathal Techtmar’s conquest of Ireland from the Aithech thuatha (Vassal Tribes) is a poem by Mael Mura of Othain AD 885. Mael Mura intimates that about 750 years had elapsed since Tuathal Techtmar had marched on the ancient British or Cruthin ritual centre of Tara to create his kingdom of Meath, which would date the invasion to the early 2nd Century AD. This is probably approximately correct. The standard pseudo-historical convention is employed, however, to make him an exiled Irishman returning with a foreign army.
The account in the Lebor Gabála Érenn, which does contain a shadow of history, is probably older and in this we see that Tuathal was born outside Ireland and had not seen the country before he invaded it. We can synchronise his invasion to early in the reign of Hadrian (122 – 138) and his death fighting the Cruthin near Antrim in the reign of Antoninus Pius (138 – 161).This fits with Juvenal (c60 to 127 AD) who wrote “We have taken our arms beyond the shores of Ireland…” Tuathal may indeed represent the fictitious Mil Espáne, or even the Ninth Legion, the Legio IX Hispana, but that we will probably never know.
The 5th and 6th centuries AD in particular are known to have been a period of unusually rapid development in the Gaelic language, as shown by the contrast between the general language of Ogham inscriptions and the earliest Old Gaelic known from manuscripts. There is little doubt that this was due to the widespread adoption of the Gaelic speech by the original inhabitants and the passage of older words and grammatical forms such as Old British(Welsh) into Gaelic. By this time, therefore, Gaelic had become, according to Heinrich Wagner, “one of the most bizarre branches of Indo-European” since “in its syntax and general structure it has many features in common with non-Indo-European languages.” These included Semitic and Hamitic influences, and point to an origin in Southern Spain, with Tarshish as the most obvious candidate.
Celtiberian or Northeastern Hispano-Celtic is the extinct Celtic language spoken by the Celtiberians in an area of the Iberian Peninsula lying between the headwaters of the Duero, Tajo, Júcar and Turia rivers and the Ebro river. This language is directly attested in nearly 200 inscriptions dated in the 2nd century BC and the 1st century BC, mainly in Celtiberian script, a direct adaptation of the northeastern Iberian script, but also in Latin alphabet.
Enough has been preserved to show that the Celtiberian language could be called Q-Celtic (like Gaelic), and not P-Celtic like British and its parent Gaulish. Celtiberian would therefore appear to be the ultimate parent Celtic tongue of the Gaelic language.