There are many artificial languages, but Loglan/Lojban has been engineered to make it unique in several ways. The following are the main features of Lojban:
Lojban's predicate grammar was derived from that of formal logic. Lojban sentences are stated as sets of arguments tied together by predicates. These predicate structures can be used to express 'non-logical' thought; logicians are able to analyze all manner of verbal expressions by converting them into predicate notation. But while Lojban will already be expressed in a predicate-based system, allowing easy logical analysis, it also contains the wide variety of elements found in natural language for expression of attitudes, emotions, and rich metaphor.
Lojban has none of the standard parts of speech. Lojban's 'predicate words' can serve as the equivalent of a noun, verb, adjective, or adverb. Action and existence are equally accessible to a speaker; the distinction can be ignored, or can be explicitly expressed. A variety of operators deal with abstractions such as events, states, properties, amounts, ideas, experience, and truth, and with at least four pre-defined varieties of causality.
Lojban has no mandatory inflections and declensions on nouns, verbs, and adjectives. Natural languages evolved such variations to reduce ambiguity as to how words are related in a sentence. Evolutionary development made these inflections and declensions highly irregular and thus difficult to learn. The simple but flexible predicate relationship erases both the irregularity and the declensions.
Tense and location markers (inflections), adverbs, and prepositions are combined into one part of speech. New preposition-like forms can be built at will from predicates; these allow the user to expand upon a sentence by attaching and relating clauses not normally implied in the meaning of a word.
Numbers and quantifiers are conceptually expanded from natural languages. "Many", "enough", "too much", "a few", and "at least" are among concepts that are expressed as numbers in Lojban. Core concepts of logic, mathematics, and science are built into the root vocabulary. On top of the core concepts of predicate logic, Lojban adds in non-logical constructs that do not affect or obscure the logical structure, allowing communications that are not amenable to logical analysis. For example, Lojban has a full set of emotional indicators, similar to such ejaculations in English as "Oh!", "Aha!", and "Wheee!", except that each has a specific meaning. Similarly, Lojban has indicators of the speaker's relationship to what is said, similar to those found in some American Indian languages.
Lojban supports metalinguistic discussion about the sentences being spoken while remaining unambiguous. Lojban also supports a 'tense' logic that allows extreme specificity of time and space relationships, even those implied by time travel. Lojban's grammar is designed to support unambiguous statement of mathematical expressions and relations in a manner compatible both with international usage and Lojban's non-mathematical grammar.
Lojban is much simpler than natural languages. Its grammar is comparable in complexity with the current generation of computer languages (such as ADA). Lojban's pronunciation, spelling, word formation, and grammar rules are fixed, and the language is free of exceptions to these rules.
This version is the first version with a stable vocabulary, and the first to have a stable and completely defined grammar (the grammar of mathematical expressions, for example, was not developed until 1990). The basic Lojban vocabulary was baselined (stabilized against change) in the last half of 1988, and the grammar similarly stabilized in late-1990, after completion of the first Lojban courses, actual usage of the language, and several iterations of careful analysis. Thus, while the language was first started 35 years ago, Loglan/Lojban is a very new language.
To ensure Lojban remains stable while people learn it, the language definition is prescribed and closely controlled. When the number of speakers has grown significantly, and a Lojban literature has developed, Lojban will be treated like a natural language and allowed to grow and flourish without constraint, as do other natural languages.
Original text and poetry has been written in Lojban, and some has been translated into the language. Lojban's powerful metaphor structure allows building new concepts into words easily, as needed. A Lojban speaker doesn't need a dictionary to use and understand millions of words that can potentially exist in the language.
There are about 800 people on our mailing lists, including about 120 listed as actively trying to learn the language. One or two dozen of these have demonstrated communicative ability to use the language in conversation, translation, or original writing, although none are yet fluent. Several of these regularly get together in the Washington DC area for conversation, and an annual meeting/mini-convention is held there in late June. This progress is remarkable since there is no dictionary for the current language, and a textbook being written exists only in partial draft form; we've evolved methods of teaching the language at a distance that overcome this handicap.
Lojban is NOT entirely unambiguous; human beings occasionally desire to be ambiguous in their expressions. In Lojban, this ambiguity is limited to semantics, metaphor, and intentional omission of information (ellipsis). Semantic ambiguity in language results because words in natural languages represent families of concepts rather than individual meanings, often with only weak semantic relationships to each other. In addition, each individual's personal experiences provide emotional connotations to words. By providing a fresh, culturally-neutral start, Lojban attempts to minimize the transference of these associations as people learn the language. By intention, most Lojban words do not closely resemble corresponding words in other languages; the differences aid in making this fresh start possible. Lojban's powerful metaphor and word-building features make it easy to make fine distinctions between concepts, discouraging individual words from having families of meanings. Lojban metaphors are themselves ambiguous, specifying a relationship between concepts, but not what the relationship is. That relationship can be made explicit using unambiguous logical constructs if necessary, or can be left vague as the speaker (usually) desires. Similarly, portions of the logical structure of a Lojban expression can be omitted, greatly simplifying the expression while causing some ambiguity. Unlike in the natural languages, though, this ambiguity is readily identified by a reader or listener. Thus all ambiguity in Lojban is constrained and recognizable, and can be clarified as necessary by further interaction.
It is known that people's ideas and thought change somewhat when they learn a foreign language. It is not known whether this change is due to exposure to a different culture or even just getting outside of ones own culture. It is also not known how much (if any) of the change is due to the nature of the language, as opposed to the cultural associations.
The Sapir-Whorf hypothesis was important in linguistics in the 1950's, but interest fell off partially because properly testing it was so difficult. Loglan/Lojban is a new approach to such testing. Obviously, if a culture-independent language could be taught to groups of people, the effects of language could more easily be separated from those of culture.
Unique features of Lojban remove constraints on language in the areas of logic, ambiguity, and expressive power, opening up areas of thought that have not been easily accessible by human language before. Meanwhile, the formal rigidity of the language definition allows speakers to carefully control their expressions (and perhaps therefore their thought processes). This gives some measure of predictive power that can be used in designing and preparing for actual Sapir-Whorf experiments.
One of the prerequisites of a Sapir-Whorf experiment is an international body of Lojban speakers. We need to be able to teach Lojban to subjects who know only their native (non-English) tongue, and we need to know in advance the difficulties that people from each language and culture will have in learning Lojban. Thus, the Lojban community is actively reaching out to speakers of languages other than English.
Lojban does not need to prove or disprove the Sapir-Whorf hypothesis in order to be successful. However, if evidence is produced supporting the Sapir-Whorf effect, Lojban will likely be perceived as an outstanding tool of analytical and creative thought.
Such a pre-definition, a language 'prescription', makes an AL a unique tool for studying the nature of language. As people learn the language, the way they 'acquire' understanding of that prescription can tell scientists how 'natural' the prescribed forms are. Actual usage of the language can be compared to the prescription providing quantitative data on specific patterns of usage. As the language evolves from its relatively pristine initial state, it may deviate from its prescription. Such deviations will better inform researchers as to the properties of a 'natural' language. The process of language change itself will be open to investigation in a way never before possible. Finally, the existence of a relatively complete language prescription at the birth of the language means that a 'description' of actual usage after that initial state can be more simply created, maintained, and studied.
Lojban is undoubtedly the most carefully designed and defined AL ever created. All aspects of its design have been carefully engineered by several people encompassing expertise in a variety of disciplines, including linguistics. The language prescription is similarly the most complete of any language. As such, it serves as a unique basis for the study of language usage and language change.
A new language like Lojban, with no native speakers, is a 'pidgin'. As the language evolves, native speakers of other languages will learn it, and will bring into their Lojban usage the perspective and patterns of their native language. This interaction process, called 'creolization', affects all languages, and may be the principle cause of language change. As Lojban is learned by speakers of a variety of natural languages, this process can be studied directly in a way never before possible, with the language prescription serving as a standard by which deviations associated with speaker ori- gin, and evolution of usage, can be measured and described in detail.
An AL like Lojban has neither an associated 'native accent' nor a culture base. Being much simpler and more regular than a natural language, an adult speaker should acquire a fluency seldom achieved when studying a natural language, and in a relatively short time. Lojban thus makes possible relatively short-term studies of language learning and language change. Processes that take generations in natural languages may be observed in a few years in Lojban speakers.
With the learning of other languages acquiring critical importance in today's international economy, Lojban provides a tool for research in language acquisition. Again, Lojban's simplicity allows the results of such research to be obtained more quickly than in similar studies of natural language acquisition.
No claim is made that studying Lojban will tell 'all' about language. Lojban, at least for several decades, will only be a 'model' of a language, whose 'naturalness' will be suspect. However, to the extent that Lojban serves the communicative and expressive functions of human language, any theory about the nature of human language must apply to Lojban. Language features and processes more easily identified in studying Lojban can then be confirmed in natural languages. Similarly, theories of the nature of language can be tested and refined against this simpler model of a language before facing the more difficult and time-consuming testing and analysis involved in natural language research.
Because Lojban is relatively culture-free, and because of its prescribed structure that is consistent with predicate logic, Lojban is an ideal medium for the analysis and description of other languages. Currently, features in language must be compared against other natural languages, and are usually described in scientific literature by glossed translation into English. Lojban is simple and regular enough to be acquired as a metalanguage for describing other languages; its structures allow clearer reflection of the patterns of the language being described, without interference from the competing patterns of English.
Finally, Lojban's predicate grammar, makes it eminently suited for ongoing computer research into natural languages. Lojban can be used for parsing and analysis, as an internal medium of data storage, or as an intermediate language for machine translation. Having a combination of logical and natural language structures, Lojban combines the best of both major structural approaches to language processing in computers.
The exercise of trying to invent a language can teach us things about language that probably can't be learned in any other way. Even if Lojban should fail as a language, we will learn. However, to the extent Lojban succeeds, its potential as a basis for testing ideas about language, its structure, and usage, is unlimited. The invention of Lojban is the invention of the science of experimental linguistics.
Those with a computer background can lead development of the first computer applications for the language. Expertise in the language will no doubt be valuable as Lojban becomes recognized as a useful tool for computer applications by the computer industry. Computer-oriented Lojbanists can also aid in developing computer-aided instruction tools or converting existing software to run on new computers.
Regardless of background, learning Lojban is a mind-expanding experience. Learning any language other than your native tongue broadens your perspectives and allows you to transcend the limited viewpoints of your native language culture. Lojban, being much simpler to learn than natural languages, provides this benefit much more quickly than does the study of other languages. Being so strongly different, the intensity of the effect seems to be heightened. When Lojbanists talk about language, the discussion has been observed to be more sophisticated as well as qualitatively different from the talk of students of second natural languages.
The logical organization embedded in Lojban aids in organizing and clarifying thoughts. Having done so, your new perspective on language, ambiguity, and communication will allow you to express those thoughts more clearly, even when you use an ambiguous natural language.
A relatively short study of Lojban by high school (or younger) students has been proposed, providing the linguistic understanding that was once associated with studying Latin and other languages for much longer periods of time. Such study can be tied in with concepts of logic, and possibly with computer-related activities, helping to show the essential interrelated nature of language and other human endeavor.
You needn't learn Lojban for any practical purpose, however. Many of those learning Lojban are doing so because it is fun. Learning Lojban is intellectually stimulating, and provides human interaction and mental challenge. Lojban has all the benefits of games designed for entertainment, with the added prospect of developing useful skills as a side benefit. Learning Lojban as an 'intellectual toy' means that you can get enjoyment from learning Lojban without nearly the effort needed to benefit from studying other languages. While becoming fluent in Lojban will probably take hundreds of hours over several months, you can feel some sense of accomplishment in the language after just a few hours of study. You can use Lojban immediately for fun, while gaining skill with greater experience.
We encourage new people to concentrate on vocabulary. Almost any use of Lojban requires some mastery of the basic vocabulary (1000-2000 words). You can learn enough Lojban grammar to support conversation in just a couple of hours, but face many hours of vocabulary work in order to effectively use that grammar. We distribute flash cards and have developed flash card techniques that are extremely efficient in learning vocabulary. These techniques have been automated into computer-aided-teaching programs sold under the name "LogFlash", with MS-DOS and MacIntosh versions currently available.
You can learn the Lojban grammar in several ways, including study of examples in the quarterly journal ju'i lobypli or by inspection and analysis of YACC and E-BNF formal grammar descriptions. Draft lesson materials (about 320 pages) are the best materials available for self-study. A Lojban text-book is being written to reflect what is learned from the first learning efforts, and is being designed so that it can be used for self-instruction, classroom teaching, or group study. A formal 'Lojban dictionary' will replace most of the existing word lists and language description materials, probably about a year after the textbook is done, but present materials contain the equivalent of a basic dictionary.
Approximately 6 months after the dictionary is published the Lojban language definition will be baselined (frozen) for 5 years, and Lojban will thereafter be solely controlled by speakers of the language.