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 (12 years or older) spends 3 hours a day of good (no playing around) study.
3. The attributes --
   1. 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.
   2. It has to be a mute or a silent language (at the beginning) in order for it to carry all natural verbal languages as its dialects.
   3. 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.

1. logically linked linear chain acts as a chain or a system of logically linked mnemonic.
2. a closed set means that the parts (radicals) of all vocabulary of a language will not contain any symbol beyond (or outside of) the given root word set.

After the inception of the PreBabel site on July 14, 2009, it has caught many people's interest. An in-depth discussion on the PreBabel took place at "conlanger bulletin board." Many great questions and critiques were discussed there. The following is a brief summary of those discussions.

1. Day one --- Summary of questions and critiques
2. Day two --- Is a universal language possible?
3. Day three --- What are the criteria for a universal language?
4. Day four --- The history of finding the universal language root word set
5. Day five --- The choices of roots for the universal language
6. Day six --- Theoretical framework of a universal language
7. Day seven --- Test procedure for validating a universal language
8. Day eight -- The fuzzy logic and the PreBabel root word set
9. Day nine --- Are all natural languages isomorphic among one another?
10. Day ten --- PreBabel root word set is invented, not discovered

11. Day eleven --- Private Language Thesis (PLT) and the types of language
12. Day twelve --- Can any language be without verbs?
13. Day thirteen --- The regression encoding procedure (REP) for PreBabel
14. Day fourteen --- The attractor theorem and a universal language
15. Day fifteen --- The innate meaning of a word token (of PreBabel) vs its semantic meaning
16. Day sixteen --- Is English a universal language?
17. Day seventeen --- A premise must be testable
18. Day eighteen --- The method of handling any chaotic system, such as the system of natural languages
19. Day nineteen --- Via PreBabel to learn any second language is to learn two instead of one, then, why do it?
20. Day twenty --- A true Emperor cannot be discredited by any disbelieving person

21. Day twenty-one --- Is Esperanto a universal language?
22. Day twenty-two --- The strategy of constructing a universal language
23. Day twenty-three -- Should PreBabel words be intuitive? And, the PreBabel a, b and c.
24. Day twenty-four -- Can PreBabel (language x) be learned easier than the language x itself?
25. Day twenty-five -- About "words and concepts of one language are grouped differently in another language.
26. Day twenty-six -- The PreBabel process is as easy as 1, 2 and 3.
27. Day twenty-seven -- How and when can PreBabel (Proper) emerge?
28. Day twenty-eight -- more about intuitiveness.
29. Day twenty-nine -- about memory anchors on learning a language.
30. Day thirty -- about tests for PreBabel.

31. Day thirty-one -- about PreBabel (Chinese).
32. Day thirty-two -- the debut of PreBabel (Chinese) at AP Annual Conference 2007 (CollegeBoard).
33. Day thirty-three -- traditional Chinese etymology vs PreBabel (Chinese).
34. Day thirty-four -- the first constructed language, the Lii character set.
35. Day thirty-five -- phonological reconstruction vs PreBabel (Chinese).
36. Day thirty-six -- more about the construction of the Lii character set.
37. Day thirty-seven -- Published works on PreBabel (Chinese).
38. Day thirty-eight -- more of traditional Chinese etymology vs PreBabel (Chinese).
39. Day thirty-nine -- PreBabel methodology I -- equivalent transformation.
40. Day forty -- Types of conlang and more on traditional Chinese etymology vs PreBabel (Chinese).

41. Day forty-one --- PreBabel epistemology: the Occam's razor.
42. Day forty-two --- axiomatic domain, theory and system
43. Day forty-three --- about Sapir-Whorf hypothesis
44. Day forty-four --- About the differences among languages
45. Day forty-five --- Reasons being in the dark
46. Day forty-six --- about large and complex system
47. Day forty-seven --- A constructed linguistic universe (I)
48. Day forty-eight -- about China's language policy
49. Day forty-nine --- Construced linguistic universe (II)
50. Day fifty -- Constructed linguistic universe (III)

51. Day fifty-one -- Constructed linguistic universe (IV)
52. Day fifty-two -- Constructed linguistic universe (V)
53. Day fifty-three -- Constructed linguistic universe (VI)
54. Day fifty-four -- Constructed linguistic universe (VII)
55. Day fifty-five -- Summary of constructed linguistic universe
56. Day fifty-six -- Discovering the PreBabel principle
57. Day fifty-seven -- Benefits of PreBabel
58. Day fifty-eight -- the PreBabel procedures
59. Day fifty-nine -- about Chinese Etymology
60. Day sixty -- Can the parts be larger than the whole?

61. Day sixty-one -- Sapir-Whorf Hypothesis revisited
62. Day sixty-two -- The two step PreBabel procedures
63. Day sixty-three -- Can linguistics be justified with math laws?
64. Day sixty-four -- About heavily inflecting or agglutinating languages
65. Day sixty-five -- Can any theory be based on only two highly atypical examples?
66. Day sixty-six -- Can PreBabel encompass the Martian language?
67. Day sixty-sevenCan the word Ēj be dissected and decoded with the PreBabel root set?
68. Day sixty-eight -- Comparison the PreBabel (Chinese) with some old school ways
69. Day sixty-nine -- Comparison (II)
70. Day seventy -- Comparison (III)

71. Day seventy-one -- Comparison (IV)
72. Day seventy-two -- Comparison (V)
73. Day seventy-three -- Sapir-Whorf Hypothesis again
74. Day seventy-four -- the "center of gravity" for new linguistics
75. Day seventy-five -- the reviews and the material facts on PreBabel (Chinese)
76. Day seventy-six -- Is PreBabel just an oligosynthetic written Lojban?
77. Day seventy-seven -- About the flexibility of language
78. Day seventy-eight -- About the universal grammar
79. Day seventy-nine -- The "Large Complex System Principle" (LCSP) & the Martian Language Thesis
80. Day eighty -- The three tiers of axiomatic system hierarchy

81. Day eighty-one -- Universal grammar -- the total freedom
82. Day eighty-two -- Spider Web Principle and the Minimum Complexity Theorem
83. Day eighty-three -- Life system is the Totality
84. Day eighty-four -- SULT is a language continuum