Engineered languages are constructed languages devised to test or prove some hypotheses about how languages work or might work. There are at least three subcategories, philosophical languages (or ideal languages), logical languages (sometimes abbreviated as loglangs), and experimental languages. Raymond Brown describes engineered languages as "languages that are designed to specified objective criteria, and modeled to meet those criteria".

Some engineered languages have been considered candidate global auxiliary languages, and some languages intended as international auxiliary languages have certain "engineered" aspects (in which they are more regular and systematic than their natural language sources).

Logical languages

Logical languages are meant to allow (or enforce) unambiguous statements. They are typically based on predicate logic

Predicate logic

In mathematical logic, predicate logic is the generic term for symbolic formal systems like first-order logic, second-order logic, many-sorted logic or infinitary logic. This formal system is distinguished from other systems in that its formulae contain variables which can be quantified...

 but can be based on any system of formal logic

Logic

In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

. The two best-known logical languages are the predicate languages Loglan

Loglan

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...

 and its successor Lojban

Lojban

See also discussed by Arthur Protin, Bob LeChevalier, Carl Burke, Doug Landauer, Guy Steele, Jack Waugh, Jeff Prothero, Jim Carter, and Robert Chassell, as well as , the concepts which "average English speakers won't recognize" because most of them "have no exact English counterpart".Like most...

, which aim to eliminate syntactical ambiguity and reduce semantic ambiguity to a minimum. In particular, the grammar of Lojban

Lojban grammar

Lojban is a constructed, human-speakable and machine-speakable language, based on predicate logic. It is one of the latest languages, designed in 1987 with most of its grammar from Loglan and some features from Láadan. Most of its root words are derived from the 6 widely spoken natural languages,...

 is carefully engineered to express such predicate logic in an unambiguous manner. Ceqli is a derivative of Loglan which aims to retain the power of unambiguous expression but allow the speaker to trade concision for unambiguity.

Philosophical languages

Philosophical languages are designed to reflect some aspect of philosophy, particularly with respect to the nature or potential of language. John Wilkins

John Wilkins

John Wilkins FRS was an English clergyman, natural philosopher and author, as well as a founder of the Invisible College and one of the founders of the Royal Society, and Bishop of Chester from 1668 until his death....

' Real Character

An Essay towards a Real Character and a Philosophical Language

An Essay towards a Real Character, and a Philosophical Language is the best-remembered of the numerous works of John Wilkins, in which he expounds a new universal language, meant primarily to facilitate international communication among scholars, but envisioned for use by diplomats, travelers, and...

 and Edward Powell Foster's Ro constructed their words using a taxonomic tree. Vocabularies of oligosynthetic languages, for example Ygyde are made of compound words, which are coined from a small (theoretically minimal) set of morpheme

Morpheme

In linguistics, a morpheme is the smallest semantically meaningful unit in a language. The field of study dedicated to morphemes is called morphology. A morpheme is not identical to a word, and the principal difference between the two is that a morpheme may or may not stand alone, whereas a word,...

s. Suzette Haden Elgin

Suzette Haden Elgin

Suzette Haden Elgin is an American science fiction author. She founded the Science Fiction Poetry Association, and is considered an important figure in the field of science fiction constructed languages...

's Láadan

Láadan

Láadan is a constructed language created by Suzette Haden Elgin in 1982 to test the Sapir–Whorf Hypothesis, specifically to determine if development of a language aimed at expressing the views of women would shape a culture; a subsidiary hypothesis was that Western natural languages may be better...

 is designed to lexicalize and grammaticalize the concepts and distinctions important to women, based on muted group theory

Muted group theory

Muted Group Theory developed out of the cultural anthropology field, but more recently has been developed in communication mostly as a feminist and cross-cultural theory...

. Sonja Elen Kisa's Toki Pona

Toki Pona

Toki Pona is a constructed language, first published online in mid-2001. It was designed by translator and linguist Sonja Elen Kisa of Toronto....

 is based on minimalistic

Minimalism

Minimalism describes movements in various forms of art and design, especially visual art and music, where the work is set out to expose the essence, essentials or identity of a subject through eliminating all non-essential forms, features or concepts...

 simplicity, incorporating elements of Taoism

Taoism

Taoism refers to a philosophical or religious tradition in which the basic concept is to establish harmony with the Tao , which is the mechanism of everything that exists...

.

Experimental languages

An experimental language is a constructed language

Constructed language

A planned or constructed language—known colloquially as a conlang—is a language whose phonology, grammar, and/or vocabulary has been consciously devised by an individual or group, instead of having evolved naturally...

 designed for the purpose of exploring some element in the theory of linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

. Most such languages are concerned with the relation between language and thought

Language and thought

A variety of different authors, theories and fields purport influences between language and thought.Many point out the seemingly common-sense realization that upon introspection we seem to think in the language we speak...

, however, languages have been constructed to explore other aspects of language as well. In science fiction

Science fiction

Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

, much work has been done on the assumption popularly known as the Sapir–Whorf hypothesis

Sapir–Whorf hypothesis

The principle of linguistic relativity holds that the structure of a language affects the ways in which its speakers are able to conceptualize their world, i.e. their world view...

.

External links

• Garrett's Links to Logical Languages
• Conlang Directory: Logical
• Origin of the term "engelang", by And Rosta (CONLANG mailing list post, 19 July 2007)