Artificial Languages

Esperanto

• Basis-Woordenschat Esperanto
• Esperanto-English Dictionary
• Vortareto de hejmajoj en Esperanto
• Esperanto Translator (from 7 languages)
• Esperanto Hardback and CD Specialty Dictionaries
• Esperanto Language Books and Other Resources

For related Esperanto language resources see:
Esperanto grammars

Tolkien Languages

• Quenya Wordlists
• Sindarin Dictionary project
• Sindarin-English Online Dictionary
• Dictionary of Elvish Languages (A-E as of May 15, 2004)
• English to Elvish Dictionary Article

For related Tolkien language resources see:
Tolkien Language Grammars

Other Languages

• The Universal Translator Assistant Project
• Cispa-English and Other Dictionaries
• Klingon-English Phrasebook
• New Klingon Words (Institute of the Klingon Language)
• Lojban-English Online Dictionary
• Romulan Word List
• Slovio, the Universal Slavic Language
• Üqoi-English Dictionary
• Vulcan-English Dictionary
• Constructed Language Index