Luwian language
Palmer was one of the linguists who were investigating the theories that some unknown language or languages were spoken in prehistoric Greece before the settlement of Proto-Greek speakers in the area. So this is the question of an ancient linguistic Pre-Greek substrate in Greece. According to Palmer, this may have been one of the ancient Anatolian languages, perhaps a Luwian language. He suggested that the language of Linear A might be Luwian on the basis of -ss- and -nd- (corresponding to -ss- and -nth- in mainland Greece) placenames being widespread in Western Anatolia.