Arcadocypriot, or southern Achaean, was an ancient Greek dialect spoken in Arcadia in the central Peloponnese and in Cyprus. Its resemblance to Mycenaean Greek, as it is known from the Linear B corpus, suggests that Arcadocypriot is its descendant.
Proto-Arcadocypriot (around 1200 BC) is supposed to have been spoken by Achaeans in the Peloponnese before the arrival of Dorians, so it is also called southern Achaean. The isoglosses of the Cypriot and Arcadian dialects testify that the Achaeans had settled in Cyprus. As Pausanias reported:
Agapenor, the son of Ancaeus, the son of Lycurgus, who was king after Echemus, led the Arcadians to Troy. After the capture of Troy the storm that overtook the Greeks on their return home carried Agapenor and the Arcadian fleet to Cyprus, and so Agapenor became the founder of Paphos, and built the sanctuary of Aphrodite at Palaepaphos (Old Paphos).
The establishment happened before 1100 BC. With the arrival of Dorians in the Peloponnese, a part of the population moved to Cyprus, and the rest was limited to the Arcadian mountains.
According to John T Hooker, the preferable explanation for the general historico-linguistic picture is
"that in the Bronze Age, at the time of the great Mycenaean expansion, a dialect of a high degree of uniformity was spoken both in Cyprus and in the Peloponnese but that at some subsequent epoch the speakers of West Greek intruded upon the Peloponnese and occupied the coastal states, but made no significant inroads into Arcadia."