yī​jiā​rén​bù​shuō​liǎng​jiā​huà

to be frank among friends and family

一家人不说两家话 一家人不說兩家話 yī​jiā​rén​bù​shuō​liǎng​jiā​huà
to be frank among friends and family
Family members speak frankly with one another rather than politely as if they were from different families; close friends or relatives do not need to be overly formal or deferential
to stick together
People from the same family or group should be united and support one another