Frank Herbert's Dune is science fiction set in the distant future, but often talks about real cultures and religions from the old Earth.

One language that's mentioned frequently is "Chakobsa".

According to Wikipedia,

Chakobsa is a Caucasian hunting language (possibly dead) from the region of modern Dagestan.

Herbert presumably took the name from Chakobsa, the "hunting language" of the Caucasus (cf. Lesley Blanch, The Sabres of Paradise (1960), p. 21), an anglicized form of Adyghe щакIуэбзэ /šhak'oe-bze/ "hunter's language" (щакIуэ 'hunter,' бзэ 'language').

An extended quote from the same book, another source, and a discussion can be found here:

So the princes have a special language of their own, a language that is understood only by the prince and his peers. This is the famous hunting language. It was contrived by the inhabitants of the knights’ citadels, the princely palaces, and the robbers’ strongholds. The secret of it is strictly guarded, and no outsider has hitherto succeeded in becoming familiar with it though it is current throughout the whole of the mountains and among all the members of the caste. It is said to be the language of an extinct line of knights; but only within the last few decades has it come to be known about at all, so secretive were the princes. All important business is discussed in this language, secrets that no man must hear, and enterprises which affect the fate of the mountain people. Only five words of it are known to science, and they resemble no single word of any other known language. Shapaka—a horse, amafa—blood, ami—water, asaz—a gun, and ashopshka—a coward. The name of the language itself is Chakobsa.

So how reputable are these sources? Was there really such a language, and does anyone know more about it or the culture from which it originated?