Lojban/Introduction to Lojban



In 1955, sociologist from Philippines Dr. James Cooke Brown began work on Loglan, a constructed language designed for linguistic research, particularly investigation of the Sapir-Whorf hypothesis, a theory stating that linguistic structures affect people's thoughts. The object was to make a language so powerfully expressive for logic and calculation that people learning it would become measurably smarter if the hypothesis was true.

He intended it to be as culturally neutral as possible, logically and linguistically powerful, incorporating all known expressive features of any language (e.g., compounded location tenses), metaphysically parsimonious (e.g., you are not required to express any feature of reality, as you are in English time-tenses of verbs), and totally regular and unambiguous. He even used maximally stable phonemes.

The formal grammar was disambiguated mechanically (at first).

The language's grammar is based on predicate logic (the name Loglan is short for "logical language"), which also makes it particularly suitable for human-computer communication, an application that led Robert Heinlein to mention the language in his novel The Moon is a Harsh Mistress.

Dr. Brown founded The Loglan Institute to develop the language and other applications of it. He always considered the language a research project that was never complete, so although he released many papers about its design he never "released" it to become a usable language. A group of his followers later formed The Logical Language Group to create the language Lojban along the same principles, but with the intention to make it freely available and encourage its use as a real language. This latter group has a small but active community of speakers.

Loglan allows very strange speech, because one can say things that are simply not meaningful. For example, you can literally say that John, a person, is a short word. Or one can directly and precisely say any of the many possible meanings of the English phrase "a pretty little girls school."

In natural languages, the ambiguity of the grammar hides these odd meanings; but in Loglan they are all available and add expressive freedom to the language. This feature is so pronounced that people fluent in Loglan say impossible things as a sort of joke — a type of humour simply not supported by the linguistic machinery of natural languages.

The oddest, most difficult thing for a speaker of an Indo-European language like English is that Loglan has no distinction between nouns or verbs, objects, direct objects, indirect objects, possessive forms or tenses. There are only predicates, with places for variables: for example, botso: X buys item Y from seller P for price Q. There are prefixes to reorder predicates; for example, price would be botso with a little word to make price the first variable. With different reorderings, one speaks of buyer, bought-thing, or seller.

Tenses for time, location, actor, type of action, etc. are provided by "little words" which are optional. Predicates compound, so a predicate can fit in the variable of another predicate. Every feature of the language has standard, regular forms for acting in compounds. For example, time-travel tenses are available trivially in Loglan (I did X from time Y to P in time Q.) using compounding forms normally used for location tenses.

After long use of Loglan, the world gains a sort of timeless, objectless, actorless flavor. Time words and location words fall away except when needed to make a point, usually with emotional emphasis. It is rather easy to avoid blame for responsibilities in Loglan, and scheduling may be creatively ambiguous because the tenses are optional.

The language is designed so that the patterns of phonemes always parse into words. Thus, one cannot babble Loglan, because even when run together, the language is still parsable.



The constructed language Lojban (SAMPA ['loZban]) was created by the Logical Language Group in 1987 based on the earlier Loglan, with the intent to make the language more complete, usable, and freely available. The language itself shares many of the features and goals of Loglan; in particular:

  • The grammar is based on predicate logic, and is capable of expressing complex logical constructs precisely.
  • It has no irregularities or ambiguities in spelling or grammar, so it can be easily parsed by computer.
  • Lojban is designed to be as culturally neutral as possible.
  • It is, nonetheless, simple to learn and use compared to many natural languages.

While the initial goal of the Loglan project was to investigate the Sapir-Whorf hypothesis, the active Lojban community has additional goals for the language, including:

  • General research into linguistics.
  • Research in artificial intelligence and machine understanding.
  • Improved human-computer communication, storage ontologies, and computer translation of natural language text.
  • Use of language as an educational tool.
  • Personal creativity.

Lojban Grammar


All words in Lojban belong to one of three overall categories: brivla, for both common nouns and verbs; cmene, for proper nouns; cmavo, for structural particles: articles, numerals, tense indicators and other such modifiers. The cmavo are further subdivided into selma'o, which are closer to the notion of parts of speech (e.g., UI includes interjections and discursives). There is no distinct class of words for adjectives or adverbs, unlike most Indo-European languages. Most types of noun phrases are always preceded by an article; there are different articles to indicate whether it is being treated as an individual, mass, set, or typical element. Brivla do not inflect for tense, person, or number; tense may optionally be indicated by separate cmavo, and number may optionally be indicated in various ways.

As befits a logical language, there is a large assortment of conjunctions. Logical conjunctions take different forms depending on whether they connect sumti (the equivalent of noun phrases), selbri (phrases that can serve as verbs; all brivla are selbri), parts of a tanru (a construct whose closest English equivalent is a string of nouns), or clauses in a sentence.

The typology is Subject Verb Object, with Subject Object Verb also common. Word formation is polysynthetic; many brivla (all of which, except for a handful of borrowings such as alga, have at least five letters) have one to three three-letter forms called rafsi which are used in making longer words. For example, gasnu means "to make something happen"; its rafsi form of -gau regularly forms compounds meaning "to cause...x", in which the agent is in the subject place of the new predicate.

Lojban has a positional case system, though this can be overridden by marking predicate arguments with explicit case particles. For instance, bramau means "is bigger than"; the bigger thing is in first position, and the smaller is second, and the measured property in the third. So mi bramau do le ka clani means "I am bigger than you in the property of height" or "I am taller than you"; but this could also be expressed as something like fi le ka clani fe do fa mi bramau, "In height, you are exceeded by me".

  • le cinfo cu bramau le mlatu -- "The lion is bigger than the cat"
  • mi bramaugau le cinfo le mlatu -- "I make the lion bigger than the cat"

What a particular place means depends entirely on the brivla. For animals and plants the second place is the species, variety, breed, or other taxon; for verbs of measurement it is the numerical measurement, and a further place is the standard; for klama ("go" / "come") it is the destination. There may be up to five places for some brivla.

Something of the flavor of Lojban (and Loglan) can be imparted by this lightbulb joke:

Q: How many Lojbanists does it take to change a broken light bulb?
A: Two: one to decide what to change it into, and one to figure out what kind of bulb emits broken light.

This makes use of two features of the language; first, the language attempts to eliminate polysemy, that is, having a word with more than one meaning. So while the English word "change" can mean "to transform into a different state", or "to replace", or even "small-denomination currency", Lojban has different words for each. In particular, the use of a brivla such as the word for "change" ("binxo") implies that all of its predicate places exist, so there must be something for it to change into. Another feature of the language is that it has no grammatical ambiguities such as appear in English phrases like "big dog catcher", which can mean either a big person who catches dogs or a person who catches big dogs. In Lojban, unless you clearly specify otherwise with cmavo, such modifiers always group left-to-right, so "big dog catcher" is a catcher of big dogs, and a "broken light bulb" is a bulb that emits broken light (you can also avoid the ambiguity by creating a new word, so "broken lightbulb" has the intended meaning).