Ancient Plakia was interesting for what became of the Pelasgian language. Already by Herodotus’ time, the language was practically extinct. However, he notes that an old language was spoken at Plakia that could be related. This language is believed to be Indo-European, but we have no more information about it.
Personally, I find this coin interesting for its image of Kybele, which is nearly identical with that of a Baktrian coin I have. For this reason, I suspect that the Persians must have moved some people from the area around Mysia (perhaps not Mysia itself) to the city in Baktria that minted those coins.
Little else is known about the city. Although we have a rough idea where it was situated, we have not yet uncovered its ruins.