Unfortunately we know very little about the original Philistine language. According to the Bible, the Philistines originally came from Crete, and their language (we know hardly anything but a few names and vocabulary words) may be Indo-European and related to other languages of the Aegean.
When the Philistines settled on the eastern cost of the Mediterranean (12th century B.C.) they soon adopted the Semitic language of the surrounding peoples.
Whether or not this had an impact on their name giving practice, we don't know. So the name
Delilah is as likelikely to be Philistine as Semitic (Hebrew).
Sources:
Das große Bibellexikon, Brockhaus, 1996, Bd. 4
Harald Haarmann: Lexikon der untergegangenen Sprachen, München (Beck) 2002
http://en.wikipedia.org/wiki/Philistines