The universal language was either a myth (story of Babel), a self proclamation because of the political and economical supremacy (such as, Latin, Arabic, Chinese or English). If a universal language is ever possible, it must be a constructed language, and it needs some design criteria. The following is my proposal.
1. The theoretical definition -- a universal language (u-language) must be able to "re-produce" every nature language in existence. Here, the term "re-produce" is not translation. It must mean that the entire language system (vocabulary and grammar) of a selected language can be re- written with the codes, vocabulary of the u-language. In fact, this selected language must be 100% isomorphic to a subset of this u-language. Thus, English is a subset of u-language as U(English) while the Japanese is the subset U(Japanese), etc.. If such a u-language can be constructed, then a true automatic language translation machine can be built.
2. The practical constrain -- if a u-language is too difficult to learn by an average person, it will become a dead language right after its birth. The rule of the thumb is that it must not be more difficult than any nature language which is learned as a second language. In fact, the design criterion should be 10 times easier to learn than any nature language to be when it is learned as a second language. Yet, it is difficult to know what the term "10 times" means. We should give it a quantified criterion. It must be learned in 100 days when a person spends 3 hours a day in study.
3. The attributes --
a. It is a second language for every nature language. That is, no particular nature language is a pre-requisite for learning this u-language. A u-language must be learned without any particular nature language as its language environment. It must be learned as a knowledge (such as chemistry or arithmetics), not as a living habit.
b. It has to be a mute or a silent language in order for it to carry all natural verbal languages as its dialects.
c. Of course, for any word token, it can always carry a sound. However, the pronunciation of the u-language word token should be evolved with the using community. Then, the verbal of the u-language will become a true universal speaking language.
The following is my proposal for a universal language (PreBabel).
The words of many natural languages are patterns of temporally ordered sound types, and the meaning of a word does not attach to particular activities, sound, marks on paper, or anything else with a definite spatiotemporal locus.
Only very small portion of the vocabulary of natural languages is based on some kinds of root word system. The majority of them arose as a token of "you told me so." There is no chance of any kind to decode the four letter "book" to be a bound paper with printing on them. The meaning of those words is agreed by a linguistic community.
Thus, the vocabulary of all natural languages are difficult to learn even by its native people. Then, trying to memorize thousands or hundreds of thousands of those "you told me so" tokens is, indeed, a youth killing chore.
The PreBabel (PB) is a system of root words. That is, the entire system can be described with its root word set which contains only 240 members, and they can be memorized in 50 hours of study by an average person in the world. Furthermore, each root is an idea or a mental image of an action, an object, a quality or a state of a situation. Every word of its vocabulary is also a mental image which expresses the meaning of that word directly. With the mental image as the memory anchor, each word can be memorized without any effort. Thus, encoding English with PreBabel is not only linking it to a universal language but is constructing a mnemonic system for English, and it is especially helpful for those ESL students.
The PreBabel is an open-frame language. Its word token is silent, and it can be pronounced in English. Besides some seed words (about 300), the entire English vocabulary can be coded by the using Americans, and it will become a dialect of English while it becomes a true universal language in the world.
PreBabel is the true universal language, it is available at