Blissymbols differ from most of the world's major writing systems in that the characters do not correspond at all to the sounds of any spoken language.

He wanted to create an easy-to-learn international auxiliary language to allow communication between different linguistic communities.

In Semantography, Bliss had not provided a systematic set of definitions for his symbols (there was a provisional vocabulary index instead [4] (1965, pp.

Eventually the OCCC staff modified and adapted Bliss's system in order to make it serve as a bridge to English.

Nevertheless, Bliss suggested that a set of international words could be adopted, so that "a kind of spoken language could be established – as a travelling aid only".

Some linguists, such as John DeFrancis[7][8] and J. Marshall Unger[9] have argued that genuine ideographic writing systems with the same capacities as natural languages do not exist.

Another vital referent is Gottfried Wilhelm Leibniz's project of an ideographic language "characteristica universalis", based on the principles of Chinese characters.

Bliss was particularly concerned with political propaganda, whose discourses would tend to contain words that correspond to unreal or ambiguous referents.

[citation needed] The grammar of Blissymbols is based on a certain interpretation of nature, dividing it into matter (material things), energy (actions), and human values (mental evaluations).

Matter is symbolised by a square to indicate that the structure of matter is not chaotic...The symbol for energy indicates...the primeval [first age] action of our planet, the throwing-up of volcano cones...The symbol for human evaluation...suggests a cone standing on its point, a position which in physics is termed labile [likely to fall, unstable]....All words relating to things and actions refer to something real, which exists outside of our brain.

Thus natural languages are mainly oral, while Blissymbols is just a writing system dealing with semantics, not phonetics.

A further symbol called an "indicator" can be added above one of the characters in the Bliss-word (typically the classifier); these are used as "grammatical and/or semantic markers.

Since it was important that the children see consistent pictures, OCCC had a draftsman named Jim Grice draw the symbols.

In 1975, a new organization named Blissymbolics Communication Foundation directed by Shirley McNaughton led this effort.

In 1991, BCI published a reference guide [14] containing 2300 vocabulary items and detailed rules for the graphic design of additional characters, so they settled a first set of approved Bliss-words for general use.

A proposal was posted by Michael Everson for the Blissymbolics script to be included in the Universal Character Set (UCS) and encoded for use with the ISO/IEC 10646 and Unicode standards.

Some questions are still unanswered, such as the inclusion in the BCI repertoire of some characters (currently about 24) that are already encoded in the UCS (like digits, punctuation signs, spaces and some markers), but whose unification may cause problems due to the very strict graphical layouts required by the published Bliss reference guides.

Some fonts supporting the BCI repertoire are available and usable with texts encoded with private-use assignments (PUA) within the UCS.