一家人不說兩家話

yījiārénbùshuōliǎngjiāhuà ㄧ ㄐㄧㄚ ㄖㄣˊ ㄅㄨˋ ㄕㄨㄛ ㄌㄧㄤˇ ㄐㄧㄚ ㄏㄨㄚˋ

    • lit. family members speak frankly with one another, not courteously, as if they were from two different families (idiom)
    • fig. people don't need to be deferential when they ask a family member for help
    • people from the same family should stick together (and good friends likewise)

Character by character

Saying俗语俗語

Proverb谚语諺語 · In everyday use

Literally
people of one family don't speak two families' words
Meaning
Says that close people needn't use polite formalities with each other.

Sources