What is this?
Dupi (shared understanding) is a constructed language where every concept is a coordinate point in semantic space. Instead of thousands of arbitrary words, you combine a domain (what dimension of reality) with a scale value (how much).
Core idea
angry → not a word, but a coordinate: ofu (calm axis at zero = rage)
lake → ali-so (water, big)
I love you → ma lo-lo-vo sa (I romance-do you)
why? → leja jo (because, question)
ga-ga → double a domain for an adjacent concept: authority → command
Word formation
Words are formed from the most recognizable characteristic to the least recognizable characteristic required to differentiate them in the given context. This means there can be more than one possible way to refer to the same thing, same as it is in natural languages, but even more so.
For ease of common understanding, a vocabulary of words derived from the existing morphology is provided, but it does not mean deviation from it is forbidden or that it absolutely must be learned by heart to understand Dupi.
Dupi should be more-or-less understandable by learning the meanings of its morphemes and a few basic rules that can be done within a couple of hours. Fluency and ease of comprehension naturally take more time.
Design principles
Universal phonology — 15 consonants (p t k b d g f m n s l w j v z) + 5 vowels. No "r", no "th", no tones. Most people can pronounce it.
Composability — 75 morphemes combine to express anything. Ambiguity is a feature; context resolves.
Omit what is obvious — subject, tense, articles, conjunctions — anything clear from context can be dropped. alolo! (love!) is valid.;
Names are local — names of countries, places, people, and other proper nouns are not translated; the local word or name is used as-is.