The following outline is provided as an overview of and topical guide to constructed languages:

A constructed language (shortened to conlang) is a language whose phonology, grammar, orthography, and vocabulary, instead of having developed naturally, are consciously devised for some purpose, which may include being devised for a work of fiction. A constructed language may also be referred to as an artificial, planned or invented language, or (in some cases) a fictional language. Planned languages (or engineered languages/engelangs) are languages that have been purposefully designed; they are the result of deliberate, controlling intervention and are thus of a form of language planning.

Constructed languages can be described as all of the following:

• A priori language
• Artificial script
• Artistic language
• Constructed language
• Controlled language
• Engineered language
• Experimental language
• International auxiliary language
• Language game
• Logical language
• Musical language
• Oligosynthetic language
• Philosophical language
• Pivot language
• Relexification
• Universal language
• Whistled language
• Zonal constructed language

• List of constructed languages
• List of constructed scripts

History of constructed languages

• Akademio de Esperanto
• Centre de documentation et d'étude sur la langue internationale
• Esperanto Museum and Collection of Planned Languages
• International Auxiliary Language Association
• International Volapük Academy
• Klingon Language Institute
• Language Creation Society
• Logical Language Group
• Uniono por la Linguo Internaciona Ido

• In the Land of Invented Languages - by Arika Okrent
• The Search for the Perfect Language - by Umberto Eco