|Created by||James Cooke Brown|
|Setting and usage||engineered language for testing the Sapir–Whorf Hypothesis and other linguistic research|
|Sources||eight of the most common languages: English, Chinese (Beijing dialect), Hindi, Russian, Spanish, French, Japanese, German|
|This article relies on references to primary sources. (March 2013)|
||This article needs additional citations for verification. (March 2013)|
Loglan is a constructed language originally designed for linguistic research, particularly for investigating the Sapir–Whorf Hypothesis. The language was developed beginning in 1955 by Dr James Cooke Brown with the goal of making a language so different from natural languages that people learning it would think in a different way if the hypothesis were true. Loglan is the first among, and the main inspiration for, the languages known as logical languages, which also includes Lojban and Ceqli.
Brown founded The Loglan Institute (TLI) to develop the language and other applications of it. He always considered the language an incomplete research project, and although he released many papers about its design, he continued to claim legal restrictions on its use. Because of this, 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.
Supporters of Lojban use the term Loglan as a generic term to refer to both their own language, and Brown's Loglan, referred to as "TLI Loglan" when in need of disambiguation. Although the non-trademarkability of the term Loglan was eventually upheld by the United States Patent and Trademark Office, many supporters and members of The Loglan Institute find this usage offensive, and reserve Loglan for the TLI version of the language.
Brown intended Loglan to be as culturally neutral as possible, and metaphysically parsimonious, which means that obligatory categories are kept to a minimum. An example of an obligatory category in English is the time-tense of verbs, as it is impossible to express a finite verb without also expressing a tense.
Also, Brown intended the language to be totally regular and unambiguous. In particular, phonemes that could be confused with each other were to be avoided.
The language’s grammar is based on predicate logic, which is why it was named Loglan, an abbreviation for "logical language". This has been thought to make it suitable for human–computer communication, which led Robert A. Heinlein to mention the language in his science fiction novel The Moon Is a Harsh Mistress (1966), and as a fully-fledged computer language in The Number of the Beast (1980).
Loglan has no distinction between nouns and verbs. The predicate words can serve as verbs, nouns, adjectives or adverbs depending on where they occur in a sentence. Each predicate has its argument structure with places for arguments, which may be variables. For example: vedma, "X sells Y to P for price Q". Prefixes allow one to reorder the argument structure of predicates, to emphasize one of the variables by putting it first. For example, to make price the first variable, use ju vedma (with the "little word" ju). Similarly, the sentence can be reordered to speak about seller, ware, or buyer. Modifications for time, location, actor, type of action, and others are provided by "little words" which are optional. Predicates can be compounded: a predicate can act as an argument of another predicate, when the former is prefixed by a "little word".
The language is designed so that the patterns of phonemes always parse into words uniquely. Even when run together, the words can be separated in only one way. In Loglan, one can directly and precisely say any of the different meanings of the English phrase "a pretty little girls’ school." This feature is so pronounced that people fluent in Loglan say impossible things as a sort of joke—a type of humor not supported by the linguistic machinery of other languages. For example, in Loglan it is possible to say that John, a person, is literally a short word.
Loglan has a wide range of words used for expressing emotions and attitudes about what one is saying, but unlike natural languages, these are kept clearly distinct from the actual statements being made.
Alphabet and pronunciation 
The alphabet of Loglan has two historical versions. In that of 1975 there were only 21 letters with their corresponding phonemes. In the final version of 1989 five more phonemes had been incorporated: letter H (/h/) was added to the alphabet in 1977 by popular demand; letter Y (/ə/) was added in 1982 to work as a kind of hyphen between the terms of a complex word; letters Q (/θ/), W (/y/) and X (/x/) were added in 1986 in order to allow the incorporation of the Linnaean vocabulary of biology, and they were useful to give more exact pronunciations to many borrowed names.
|a||b||ʃ||d||e||f||g||h||i / j||ʒ||k||l||m||n||o||p||θ||r||s||t||u / w||v||y||x||ə||z|
- The letters I and U when placed before vowels will represent the IPA sounds /j/ and /w/ respectively. For example: ie /je/ ("what?"), ue /we/ ("what!" as an expression of surprise or interest).
In popular culture 
Loglan was mentioned in a couple of science fiction works: Robert A. Heinlein’s well-known books The Moon Is a Harsh Mistress and The Number of the Beast, and Robert Rimmer’s utopian book Love Me Tomorrow (1978).
Loglan’s inventor, James Cooke Brown, also wrote a utopian science fiction novel The Troika Incident (1970) that uses Loglan phrases but calls the language a different name, "Panlan".
See also 
- Brown, James Cooke (1975, 2nd edition). Loglan 4 & 5: A Loglan-English/English-Loglan Dictionary. Gainesville, Florida: The Loglan Institute, Inc.
- Brown, James Cooke (1989, 4th edition). Loglan 1: A Logical Language. Gainesville, Florida: The Loglan Institute, Inc.
- The Troika incident: a tetralogue in two parts, Author:James Cooke Brown, Publisher:Doubleday, 1970, Length:399 pages, ASIN: B0006C09JO
- James Cooke Brown, 1960. "Loglan". Scientific American 202:43–63
- Loglan in Russia (Russian) (Esperanto)
- The Loglan Institute homepage
- Loglan 1: A Logical Language
- Loglan 2: Methods of Construction
- Loglan 3: The Primer, by Stephen L. Rice
- Loglan 4: A Loglan to English Dictionary
- Loglan 5: An English to Loglan Dictionary
- mirror of loglan.org by Randall Holmes (at Boise State University's Department of Mathematics)
- June 1960 "Loglan" article by James Cooke Brown for Scientific American (hosted by the Logical Language Group)