In Indonesian, older brothers and sisters are called kakak and younger brothers and sisters are called adik

Two boys were crossing a residential street. The road stretched straight through the houses and there was a lot of traffic there. The two boys were running across the street, looking both ways. There was a big difference in height between them as they crossed the road together. They must be brothers.

In Indonesian language, brothers and sisters are called "kakak" and "adik". But interestingly, the words "kakak" and "adik" are not enough to tell the gender. What I mean is only because kakak refers to the older of the brothers and sisters and adik refers to the younger of the brothers and sisters. In other words, if you say kakak, you don't know whether it's your brother or sister.

Therfore, if you want to tell the gender, you have to add the word, "laki-laki" which means male, or "perempuan" which means female after the word. It is like kakak laki-laki. Yet the local people usually say just "kakak" or "adik". For Japanese people, it's a little bewildering.

Kinship names are different in different cultures. In English, the word "briother" can be used to describe a male sibling, but apart from Indonesian, it is possible to tell whether they are older or younger. In Chinese, paternal uncle and maternal uncle are written differently. In Indonesian, expressions that do not specify gender may be more suitable for today's gender diversification.