Alphabet of human thought
Algebraic logic
– Reasoning about equations with free variables
An Essay Towards a Real Character, and a Philosophical Language
– Book by John Wilkins
Language of thought hypothesis
– Hypothesis of philosopher Jerry Fodor
Natural semantic metalanguage
– Linguistic theory of semantic description
Philosophical language
– Any constructed language that is constructed from first principles
Upper ontology
– Ontology applicable across domains of knowledge
https://en.wikipedia.org/wiki/Alphabet_of_human_thought