List of constructed languages

Controlled languages

Controlled natural languages are natural languages that have been altered to make them simpler, easier to use, or more acceptable in certain circumstances, such as for use by people who do not speak the original language well. The following projects are examples of controlled English:

• Basic English, Special English, Globish (Gogate) and Globish (Nerriere) seek to limit the language to a given list of common-use words and terms in order to make it simpler to foreign learners or other people who may have difficulties
• Plain English proposes a more direct, short, clear language by avoiding many idioms, jargon and foreign words
• Simplified Technical English seeks to largely reduce the complexity and ambiguity of technical texts (such as manuals)
• E-Prime eliminates the verb to be with the intent of making writing more expressive and accurate.

Visual languages

Visual languages use symbols or movements in place of the spoken word. Sign languages fall in this category.

• Blissymbols (zbl)
• Gestuno
• List of sign languages

Human-usable

• An Essay towards a Real Character and a Philosophical Language by John Wilkins
• aUI
• Ilaksh
• Isotype
• Ithkuil
• Láadan (ldn)
• Loglan by James Cooke Brown
• Logopandecteision
• Lojban (jbo) successor to Loglan by the Logical Language Group
• Toki Pona by Sonja Lang

Knowledge representation

• Attempto Controlled English is a controlled natural language that is also a knowledge representation language.^[2]
• Several well known Knowledge Query and Manipulation Languages have been created from extensive research projects, to represent and query knowledge on computers:
  • Knowledge Interchange Format (KIF), a precursor for knowledge representation.
  • Common Logic (CL), an ISO standard derived from KIF.
  • Resource Description Framework (RDF), a language standardized by the World Wide Web Consortium (W3C) based on the principles of Common Logic, which represents knowledge as a directed graph built from unordered sets of "sentences" (in fact, as relational triples: subject, relation, attribute) using various syntaxes (XML, Turtle, JSON-LD, RDFa) for its interchange format. Each element of the triple can be either a simple value (if its semantic value is not specified outside of the relation using it), or identifiers of objects (such as URIs) that are part of enumeration built from another subset of relational triples. The relations may be open (in which case the attributes are not enumerable) or closed in a finite enumerable set whose elements can be easily represented as objects as well with their own identity participating in many different relations for other parts of the knowledge.
    • UML may be used to describe the sets of relations and rules of inference and processing, and SQL may be used to use them in concrete schemas and compact store formats, but RDF designs its own (semantically more powerful) schema language for handling large sets of knowledge data stored in RDF format.
    • RDF is most probably useful only for automated machine processing, but its verbosity and complex (for a human) representation mechanisms and inference rules do not qualify it as a human language except in very limited contexts. It is still a specification with extensive research.
  • Web Ontology Language (OWL), another knowledge representation language standardized by W3C, and derived from Common Logic.
• CycL
• The Distributed Language Translation project used a "binary-coded" version of Esperanto as a pivot language between the source language and its translation.
• Lincos
• Loom
• Universal Networking Language (UNL)

Languages used in fiction

Alternative languages

Some experimental languages were developed to observe hypotheses of alternative linguistic interactions which could have led to very different modern languages. Two examples include:

• Brithenig, created by the inventor of the alternate history of Ill Bethisad, Andrew Smith
• Wenedyk, a language of the alternate history of Ill Bethisad created by Jan van Steenbergen

Micronational languages

• Talossan, by R. Ben Madison

Personal languages

• Balaibalan by Muhyî-i Gülşenî
• Enochian by Edward Kelley
• Lingua Ignota, by Hildegard of Bingen
• Nakaniang Gasuk by GACB