my son Yujin calls his 2cousins here (adam's nieces) ate... adam just explained what it means when yujin met them and calling them ate.
it's also different about here calling uncles and aunties. like adam's uncles and aunties, yujin can't call them grandma or grandpa. he calls them uncle and aunt too. same as adam's cousins.. my sons can't call them aunt or uncle...
i was ask once just few days ago by one of Yujin's teacher what kuya means... i said older brother. and then she asked me if Yujin has older brothers, i said no, yujin was talking about his cousins back in the Philippines. so i explained to her that we have to use this words even if she/he is not your real brother or sister, and told her it's our way to respect people and not to call them just by their names.
it's kinda hard for us because we were brought to respect elders.. i still remember when i was young, my grandma will slap me if i forgot to say kuya or ate same as aunt/uncle and so on.