Sister and brother, how can you tell if it's a sister or a brother or a younger brother?

In English, a brother can be expressed as a brother or a brother's younger brother. This is usually to tell others that you have a brother, but if you want to explicitly say that you have a brother, you can say this: Brother, if you want to say brother, just say brother. Of course, you can also say brother. Sister and brother have the same expression.