aUI was created in the 1950s by W. John Weilgart, Ph.D. (1913-1981), a philosopher and psychoanalyst originally from Vienna, Austria. He strove to design a form of communication based on what he proposed could be fundamental, universal elements of human thought and expression. In his psychotherapy work, he sometimes used client created aUI formulations to reveal possible subconscious associations to problematic concepts.
Weilgart followed Gottfried Leibniz' proposal for an alphabet of human thought that would provide a universal way to analyze ideas by breaking them down into their component pieces—to be represented by a unique "real" character. In the early 18th century, Leibniz outlined his characteristica universalis, the basic elements of which would be pictographic characters representing a limited number of elementary concepts. René Descartes suggested that a lexicon of a universal language should consist of primitive elements. The history of this language philosophy is delineated in Umberto Eco's The Search for the Perfect Language (1995).
As a young man, Weilgart observed the pervasive and insidious effects of state planned Nazi propaganda. In particular, he was struck by how double meanings, together with similar sounds in slogans often associated unrelated words into suggestive "stereotyped formulas", [that would] "arrest the attention and appeal to the hearts of the national masses" (Hitler, Mein Kampf, 1925). For example, in one of the most repeated political slogans, Ein Volk, Ein Reich, Ein Führer! ("One people, One empire, One leader!") the word Volk sounds similar to folgt, meaning to follow or obey; Reich also means rich; so the phrase points to a subliminal association: that the populace obeys and follows their leader, who leads them to a wealthy empire. 'Blu-Bo' from Blut und Boden (Blood and Soil) was also a key slogan of Nazi ideology, as well as of course Heil Hitler! (Hail Hitler! - heil also meaning salvation, safe, well).
Based on research in semantic conditioning from the 1950s, Weilgart theorized that whereas the conscious mind links synonyms (similar meanings), the subconscious mind associates assonance (similar sounds). That is, while we think about and distinguish similar-sounding words by their different meanings, we nonetheless feel at some level that they are (or ought to be) also related in meaning. Alliterative slogans may suggest a link in words unrelated by meaning but related by common sounds. Weilgart posited that such slogans were one of the many significant factors that could lead to war under desperate and incendiary conditions. Further, he believed that the general discrepancy between homophonous and synonymous words in conventional language would add to the disconnect with the subconscious mind.
Hence, aUI's elements were designed to reflect a motivated, mnemonic relationship between sound, symbol, and meaning - with the result that if words look and sound similar, they also mean similar; homophonous words become synonymous.
Psycholinguistic research needs to be conducted to investigate some of these theories, now when so much more is known about how the brain processes language.