The following list of notable constructed languages is divided into auxiliary, ritual, engineered, and artistic (including fictional) languages, and their respective subgenres. All entries on this list have further information on separate Wikipedia articles.
International auxiliary languages (IAL) are languages constructed to provide easy, fast, and/or improved communication among all human beings, or a significant portion, without necessarily replacing native languages.
Zonal auxiliary languages are languages created with the purpose of facilitating communication between speakers of a certain group of related languages. Unlike international auxiliary languages for global uses, they are intended to serve a limited linguistic or geographic area. Examples include Pan-Slavic languages, Pan-Romance languages and Pan-Germanic 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:
Visual languages use symbols or movements in place of the spoken word. Constructed sign languages also fall in this category.
These are languages in actual religious use by their communities or congregations.
Engineered languages are devised to test a hypothesis or experiment with innovative linguistic features. They may fall into one or more of three categories: philosophical, experimental and logical.
Tolkien's most prominent languages are:
Some experimental languages were developed to observe hypotheses of alternative linguistic interactions which could have led to very different modern languages. The following two examples were created for Ill Bethisad, an alternate history project.
There is a version of Wikipedia in each of the following ten constructed languages. Eight of these languages are IALs (international auxiliary languages), while Lojban and Toki Pona are engineered languages. Until 2005, there were also versions of Wikipedia in the constructed languages Toki Pona and Klingon, but these have been deleted. Toki Pona Wiki project continued independently under the name "Wikipesija", and re-opened in 2025.