Wiktionary
n. 1 (&lit private language English) 2 (context philosophy English) 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 http://en.wikipedia.org/wiki/Ludwig%20Wittgenstein (1889-1951) to be impossible.
Usage examples of "private language".
They were the private language the Pontifex in his terrible senility had invented, and which the high spokesman alone had mastered.
And as he grew more aware of his wife's and his son's private language, the more isolated he felt.
I don't really understand why ships need such curiously specific names other than to disadvantage those who do not speak that private language.
It has its private language and its common memories, and at the approach of an enemy it closes its ranks.
Ayla didn't notice that she had slipped into the private language she had developed during her years alone with only animals for company.
I was most struck by the way in which the Colonel describes each of his sexual encounters, using French words which I don't always understand as well as a private language shared by him and his daughter.
Vonnegut's faithful readers have a sense of clubbiness that is intensified by the private language of the books.
Knowing that, Fenring spoke in code, using a private language the two friends had developed as boys.
Over the PA system, Tleilaxu Masters screamed incomprehensible orders in their private language, while the work crews muttered in subdued fear.