Subject: FAQ: Lojban and Loglan (corrected)

From: [email-masked]
Date: Wed, 24 May 2000 13:34:24 EDT

First, what do they have in common, to make the question of
differences relevant?
1. They share the first thirty years of the history of the Loglan
Project. The late Dr. James Cooke Brown started the project in 1955
and published the first report of it in the Scientific American in 1960. 
After that he led it through two cycles of funding , development and
enthusiast participation before the separation in the late 1980's. 
Loglan continued to be developed under that name by Dr. Brown's
group, The Loglan Institute, while a separate group, The Logical
Language Group, centered on Robert LeChevalier and John Cowan,
continued its development under the name Lojban. The separation
was over political issues of control of the language; it did not directly
affect the design features from the prior development.
2. First among these features, first order predicate logic formed the
basic grammar of the language. To make a usable language Dr.
Brown added such logical frills as identity, descriptions of various
sorts, variables over predicates and reduction devices to bring higher
order logic grammatically within the first order. More practically, he
added devices for carrying on conversations: ways of forming
commands, questions, exclamations, ways of expressing emotions, of
referring to the passing scene and so on.
3. But through all of this, he intended to keep the feature of first
order logic that it is uniquely decomposable, has only one possible
parsing. Early on this meant practically little more than that any
string of sounds or letters that composed a legitimate Loglan
sentence could be broken into words in exactly one way. In the end,
however, both Loglan and Lojban have grammars which uniquely --
and correctly -- parse every legitimate sentence of the language -- and
computer programs that implement these grammars. This is a feature
of no other language with a reasonable claim to be a full human
language.
4. At the heart of this system is a division of word classes on strictly
phonological grounds: primitive predicates of form C'VCCV or
CC'VCV, other predicates containing CC in their first five letters,
ending in V and having penultimate stress (and a plethora of other
conditions), names ending in C, and the remaining functional words --
the logical, emotional, conversational, words as well as much of the
necessary grammar -- spread over V, VV, CV, and CVV.
5. The primitive predicates in each language derive from words for
the corresponding concepts in the major languages of the world, in
such a way as to maximize the recognizability of the created word by
similarity -- perhaps not obvious ones -- with the home language of 
many people. In addition, each primitive predicate gives rise to one
or more unique fragments which can combine to form new predicates
with meanings derived from the meanings of the constituents. Each
such compound is, of course, uniquely decomposable into its parts.

But superficially a passage in Loglan and the same content in Lojban
will look very different. This results from some of the conditions that
created the split originally and from the years of independent
development.
1. One of the political issues was over who owned Loglan, with the
Institute claiming to have in effect a copyright on every word of the
language. To meet this problem, the Group recreated all of the
primitive predicates, using the same algorithm but 1980 statistics
(rather than 1950), which gave a new list of major languages and new
weights to them. In addition, the Lojban process took into account
the need for unique compound-building fragments, which had been
added late and ad hoc in Loglan. The result is that the two sets of
primitives are entirely different (I haven't checked but I doubt there
are more than a couple of real matches and probably as many
homonyms). The various parts of the little word (V, VV, CV, CVV)
space were also reassigned, so the distribution of items in this area
are quite different. Lojban has been quite enthusiastic in expanding
some of the original categories of little words, so that direct
correlates in Loglan are not always easy to find.
2. Further, to carry out some of these tasks, Lojban added an item
to the phonology of Loglan and changed the representation of one
sound. Lojban text contains ' and x; Loglan does not have the first
and uses h for the second.
3. Over the years, both the TLI and LLG have had to deal with a
variety of problems in their grammars. Each has found solutions for
these problems as they arose, but they have not generally found the
same solutions. Thus, the two grammars -- while they agree over a
large part of the two languages -- will give different parsing in some
cases, perhaps one even rejecting what the other accepts. 
4. Similarly, over the years each group has had to decide what
certain structures mean and how to say certain things. Again, the
decisions have been made independently and thus usually differently.
This extends even to the meaning (and place structure) of the
primitive predicates of each language. However, it is probably the
case that all the various meanings that one has accommodated the
other has also, just differently.

The grammar and basic vocabulary of Lojban are baselined and will not change 
for
some time and then only under the strongest of pressures. Loglan is 
officially still
changing but has in fact been stable for several years. Although the readily 
available
grammar programs for both languages are not the most up-to-date, they are 
enough to use for many detailed comparisons, with the expectation being that 
significant differences in grammar will appear only in rather remote and 
complex structures. The case of vocabulary comparison is less certain, but 
it seems likely that fairly regular, if not automatic, correspondences can be 
made between the two languages, probably more easily from Loglan to Lojban 
than the reverse.