Morphology: Rules of formation

These are the rules for generating Lojban words. Any speech generated following these rules will be uniquely decomposable by the PEG morphology algorithm.


  • You may not pause in the middle of any word.
  • You may pause between any two words.
  • You must pause in the following cases:
    • Before any word that starts with a vowel or diphthong or y.
    • Before and after a cmene.
    • Between a finally stressed cmavo and a brivla that starts with a cluster.
    • Between two cmavo of form CVCy (without an intervening pause) and a string of one or more rafsi (including gismu and fu'ivla as possible final rafsi).
    • Before and after a non-lojban-word.


  • A cmene can consist of any number of syllables (possibly none) and must have a final consonant or consonant cluster (details of what is a permissible final cluster still to be worked out).


  • A cmavo consists of a non-h, non-cluster syllable followed by zero or more h-syllables. (Any stress is allowed, but see pause rules.)


  • A gismu can have either CCVCV or CVC/CV forms, where CC is an initial-pair. The first vowel must be stressed and the second unstressed.


  • A fu'ivla is any string of non-y syllables such that:
    • It does not begin with h or with a consonantal-syllable.
    • Only the penultimate vocalic syllable is stressed (therefore it must have at least two vocalic syllables).
    • The last syllable ends in a vowel or a diphthong.
    • It does not begin with a cmavo-form followed by a cmavo, a gismu, a fu'ivla or a lujvo (tosmabru test).
    • It does not consist of a string of rafsi (lujvo test).
    • It does not consist of a consonant followed by a string of rafsi (slinku'i test).


  • A lujvo is any string of two or more rafsi such that:
    • It has penultimate stress.
    • The final rafsi ends in a vowel or diphthong.
    • If the first rafsi is an unstressed CVV-rafsi or is followed by another CVV-rafsi, it must be immediately followed by either an r-hyphen or n-hyphen.
    • If the first rafsi is a CVC-rafsi, and the second consonant plus what follows is a lujvo, then the CVC-rafsi must have a y-hyphen.
    • Any CVC-rafsi followed by a consonant such that the pair is impermissible requires a y-hyphen.
    • gismu and fu'ivla are allowed as final rafsi.
    • extended (brivla and fu'ivla) rafsi can only be preceded by y-final rafsi.
    • extended rafsi that begin with a vowel or diphthong take an {'} if they are preceded by another rafsi.


  • gismu-rafsi have the forms CVCCy, CCVCy, CCV, CVC(y), CVV(r/n). The parenthesized hyphens are always allowed, and sometimes required (see lujvo).
  • brivla-rafsi are any y-less brivla, minus the stress, followed by {'y}.
  • fu'ivla-rafsi is a fu'ivla that end in CV with the V changed to y if
    • it is not a string of y-less rafsi plus CVCy or CCy. (lujvy test)
    • it is not a consonant plus a string of y-less rafsi plus CVCy or CCy. (slinkujy test)

Created by xorxes. Last Modification: Thursday 21 of October, 2010 14:58:55 GMT by Eimi.