private languages

Noun

private language (plural private languages)

1. Used other than figuratively or idiomatically: see private, language.
   • [T]hey could not say much because of his presence. But it did not greatly matter, for their past was now rich enough to have given them a private language; [...]1917, Edith Wharton, chapter IX, in Summer […], New York, N.Y.: D[aniel] Appleton and Company, →OCLC, page 128
2. A language which expresses one's inner thoughts, feelings, or experiences but which cannot be used for communication, since it is known to and understandable by only one person—the existence of which was famously argued by Ludwig Wittgenstein (1889-1951) to be impossible.
   • A private language was not merely a language contingently spoken by one person. . . . A private language was meant to be semantically and necessarily private: one whose symbols could by definition be "understood only by the speaker".1986, Héctor-Neri Castañeda, edited by James E. Tomberlin, Profiles: Héctor-Neri Castañeda, →ISBN, page 85