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
It can also mean someone that never shows up to events, someone that ditches his friends esspecially or the actual act of ditching, it's commonly used in west sydney among urban and ethnic youths
come on man don't dogg us we've been planning this...
bro screw that punk you know he's a dogg don't bother inviting him