To quote Wikipedia, “Zaum are the linguistic experiments in sound symbolism and language creation of Russia-empire Futurist poets such as Velimir Khlebnikov and Aleksei Kruchenykh.
Coined by Kruchenykh in 1913, the word zaum has been translated as "transreason", "transration" or "beyonsense" According to scholar Gerald Janecek, zaum can be defined as experimental poetic language characterized by indeterminacy in meaning.
Kruchenykh, in “Declaration of the Word as Such (1913),” declares zaum “a language which does not have any definite meaning, a transrational language” that “allows for fuller expression” whereas, he maintains, the common language of everyday speech “binds.”
Examples of zaum include Kruchenykh’s poem “dyr bul schyl,” Kruchenykh’s libretto for the Futurist opera “Victory over the Sun”, and Khlebnikov’s so-called “language of the birds”, “language of the gods”, and “language of the stars”. The poetic output is perhaps comparable to that of the contemporary Dadaism but the linguistic theory or metaphysics behind zaum was entirely devoid of the gentle self-irony of that movement and in all seriousness intended to recover the sound symbolism of a lost aboriginal tongue.”
Kazimir Malevich’s Suprematist paintings are the visual equivalents of the linguistic experiments in sound symbolism and language creation of the zaum poets.