NOTE: Some of the links in the following lists direct to private groups requiring membership or log-in credentials.
General Mailing Lists
A listserv discussing international auxiliary languages.
The Conlang Mailing List (CONLANG-L)
The oldest (founded Sept. 1991) and most active online mailing list dedicated to conlanging. Good for novices all the up to professional linguists. An archive mirror of the list’s activity is available at archive.conlang.org
ElfLING (Elvish Linguistics Mailing List)
Created by David Salo in 1998, Elfling is an active listserv dedicated to Tolkien’s conlangs. There is a FAQ page at nellardo.com/lang/elf/faq.html. The list is used for everything from help with translations to/from Sindarin and Quenya to scholarly discussions of Elvish linguistic topics.
From site: “Germaniconlang is another offshoot of the Constructed Languages List, along with Celticonlang (last post 11/8/2010), Romanceconlang, Slaviconlang, Westasianconlangs, and Eastasianconlangs [Note: No Yahoo! Group as of 10/10/11). As the name suggests, it is devoted to those constructed languages that are based on or inspired by the Germanic languages. The possibilities are numerous: a revivied version of Gothic, an alternative spelling for English, a pan-Germanic language understandable to any native speaker of a Germanic language… You name it! Anyone who is interested in Germanic linguistics, created a Germanic conlang, or hopes to create it one day, is sincerily invited to participate.”
An online forum dedicated to conlanging and conworlding and fiction featuring such.
Conlanger.com Bulletin Board (CBB)
An online forum dedicated to conlangs, conworlds, concultures, and linguistics. CBB also includes sections for speakers of German, Spanish, French, Dutch, “Scandinavian,” and “other languages.”
Constructed Languages LiveJournal
Created by Sai Emrys, this site provides another online forum for beginning to experienced conlangers.
CWS, or ConWorkShop is a conlanging community and tools website started in early 2014 aimed at providing the tools and community to help you strive in your conlanging endeavours. We are a very eclectic group of people who are enthusiastic about conlangs and concultures. We have teenagers, students, professionals, and so on – everyone is welcome.
Zompist Bulletin Board (ZBB)
An online forum dedicated to the discussion of conlangs, conworlds, linguistics, and Mark Rosenfelder’s Almea. One of the (if not the) most active conlang-related forums on the Internet.
Non-English Conlanging Forums
French conlanging and conworlding forum
Conlanger: Polskie Forum Jęykotwórców
Polish conlanging and conworlding forum
A Spanish-speaking Facebook community of conlangers.
IdeoLengua: Lingüística e Idiomas Artif
Spanish conlanging mailing list. From site: “La lista no moderada de correo IdeoLengua pretende ser un espacio de encuentro y discusión en castellano sobre lingüística e idiomas artificiales.”
НЕ зсперанто / NE Esperanto
Conlanging sub-forum on the Russian Esperanto forum
A sub-reddit devoted to discussion of John Quijada’s Ithkuil philosophical language.
Klingon Language Discussion Mailing List
Established in 1999 by the Klingon Imperial Diplomatic Corps, this group serves as a meeting place for novice level students to discuss topics related to the Klingon language and its usage.
The online community of learners of the Na’vi language from Avatar
Online community of learners of the Dothraki language of the HBO series Game of Thrones
An extensive site for both information as well as learning Esperanto
Lojban: Lojbanic Forums
Various forums and mailing lists in which people discuss Lojban itself or discuss in Lojban.
Toki Pona Forums
Forums dedicated to learning and discussing issues pertinent to toki pona
tlhIngan-Hol Mailing List [Klingon]
Sponsored by the Klingon Language Institute, this mailing list has archives going back to 1993. An excellent resource for students of Klingon of all levels.
A wiki/forum intended as the ‘internet encyclopedia of creative counterfactuality.’
C’est une encyclopédie collaborative francophone, qui traite principalement des idéolangues (ou langues construites), des univers et cultures imaginaires qui s’y rattachent ainsi que de leurs inventeurs.
Described as ‘aimed at facilitating the development and creation of constructed languages, conlangs.’
Anthologica is a collaborative site for conlangers that offers wiki hosting, online dictionary management, and a forum.
Conlang/Concultural Card Exchange
Begun in 2009, this project allows conlangers and conworlders to exchange greetings (e.g., greeting cards, postcards, etc.) in their own languages as well as in their own con-cultural milieu.
Conlang Twibe on Twitter
The Twitter group of conlangers
Conlangs! Constructed Languages in Literature
Goodreads group for people who write, read or are otherwise interested in conlangs (constructed languages) in literature of all kinds – both fiction which features a conlang, or non-fiction books about conlangs and/or conlanging.
Conlangs on Facebook
With links to ZBB, Conlang, etc., but also a consolidated site for posting photos and more.
Conlangers and Conworlders
Conlangers on Google Plus
Conlangers on Deviantart
The conlanging community at Deviantart, the ‘largest online social network for artists and art enthusiasts.’
Conlanging Subreddit on Reddit
The conlanging community on Reddit, “the front page of the internet”.
An extensive conlanging directory in Dutch
Language Creation Society (LCS)
The official homepage of the LCS with links to the Language Creation Conferences, LCS Podcasts, and much more. Mailing lists available from the LCS are available at lists.conlang.org/listinfo.cgi