Early Greek and Roman scribes such as Herodotus (450 BC) and Polybius (200 BC) make reference to a loose ethnic grouping as the Keltoi or Galli in their written histories: a largely tribal society of warlike, iron-based communities. The similarity in stone inscriptions and artifacts discovered in Europe and Britain dating from this period points towards a form of shared language. The Keltoi described in the ancient Greek histories were the early Celts, dispersed as far north as the Iberian Peninsula and to the Scottish highlands in the north. Although there are undoubted similarities between these tribal groups in terms of linguistic unity (e.g. alphabetic symbols and verb, subject, object word order), the chronicles of the ancient historians are contradictory and confusing. The Roman writer Tacitus stated that the language spoken by the Gauls was very similar to the language spoken by the early Britons. Julius Caesar, however, saw little similarity and noted that the three principal tribes of Gaul spoke in noticeably distinct dialects. As a result, to view the Celtic languages as belonging to one unified ethnic grouping is problematic, with modern historians preferring to divide the various dialects and forms into two distinct groups: Continental Celtic and Insular Celtic. The first of these groupings, Continental Celtic, comprises Leontic (spoken in the southern Alpine region), Celtiberian (spoken in parts of north-eastern Spain and Portugal), Gallaecian (France and northern Alpine region). The second grouping, Insular Celtic, comprises two distinct linguistic families: Goidelic and Brythonic, which subdivide into other related languages. The former (Goidelic) includes Irish and Scottish Gaelic and Manx and the latter (Brythonic) Pictish and Cumbric (both extinct), British [Common Brittonic], Welsh, Breton and Cornish. As virtually all Continental Celtic is now extinct, exact geographical boundaries are a matter of vague approximation. In all probability, certain tribes were nomadic in aspect and this added to a crossing and merging of dialects, hence the conflicting views of Julius Caesar and Tacitus.
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