Family phrases as a private kinship language
A family builds a private stock of phrases and sayings that are meaningless to outsiders but carry the whole shared past for its members. Years later, siblings who are scattered and estranged can recognize each other as family by quoting a single phrase, such as 'We haven't come to Bergamo on a campaign.' The lexicon works like a dead language or hieroglyphics: it outlasts the circumstances that produced it and remains the proof that a group once existed as a unit.