Ulleh is NOT greek, it's actually in a Lebanese Arabic accent, it is most definently NOT just a random saying. it's actually a slang way of saying "you" equivilent to "man" in english. In the Iraqi Arabic accent it's actually pronounced "willeh" or "willak (short "lak"). It's mildly offensive to elders or people of a respectable status within the community.
be carefull when going out ulleh the fuckin cops are doing happy laps in the area