I thought of the phrase “family lexicon” independently, in connection with an idea that certain words or phrases, through repetition and association, build family ties, establish identity. I also suspect that some words — possibly the same ones, but possibly not — establish the identity of individuals, set boundaries, alliances, oppositions within that group.
I found Ginzburg’s book by googling the phrase. It’s a splendid achievement — she really does let a reader in on the way a phrase, repeated in changing, expanding situations, begins to establish identity, becomes the mark of an underlying continuity of associations and with them, a sense of participation. Would members of this group have the same relationship to the “lexicon”? I don’t think she delved into the different potential associations a individual members may have had.
Before I learned of Ginzburg’s book, I used the phrase (incorrectly, I think in retrospect) as the domain name for a website of family photographs. The project crashed and burned for the best of reasons.