Herodotus gives us a clear instance of language shift with respect to the Athenians who shifted from Pelasgian
to Greek, ([TEXT NOT REPRODUCIBLE IN ASCII.
By positing continuity from semi-mythical Pelasgians
(mentioned by Homer and Herodotus) and asserting that ancient Macedonia, Epirus and Illyria were in some sense Albanian states, they devised a list of precursors for Zog which included Achilles, Alexander the Great, Pyrrhus and Queen Teuta.
Herodotus comments early in his history that Greece was originally occupied by Pelasgians
who spoke a non-Greek language.
The Greek seems to be, in a great measure, a simple, uncompounded language, formed from the primitive jargon of those wandering savages, the ancient Hellenians and Pelasgians
, from whom the Greek nation is said to have been descended.
The phrase, `they had never yet migrated', could hardly refer to the Pelasgians
by contrast with the Hellenes,(13) but well suits the Athenians contrasted with the Spartans: and as for the shift from [Greek Words Omitted] to [Greek Words Omitted], there is one similarly abrupt, though in the other direction, at 4.
35) Hellanicus in his Phoronis included a history of the legendary Pelasgians
and enumerated their kings.
In the Juventus the emphasis on nationality was even stronger, because he began by describing the pastoral and cultivating Pelasgians
as the indigenous inhabitants of both the Greek and Italian peninsulas and the Achaians as a greater people coming in from outside, eventually, he suggested, to absorb them.