Learn the Alien Languages of Star Trek: a Masterpost
Vulcan Language Research Project
Vulcan Language Dictionary
Vulcan Writing Systems at Omniglot
Vulcan Language at Memory Alpha
Vulcan Language Institute
Vulcan Language Official Tumblr (No longer active, but still good info)
Cardassian Language Tumblr
Cardassian Writing System Part 1
Cardassian Writing System Part 2
Cardassian Writing System Part 3 (Numbers)
Cardassian Language at Memory Alpha
KlingonTeacher on Youtube
Learn Klingon Facebook Group
The Klingon-English Dictionary by Marc Okrand PDF
Klingon Language at Memory Alpha
Klingon Language Institute
Klingon Language Assistant App (For Android Phones only)
Klingon for the Galactic Traveler by Marc Okrand
Conversational Klingon by Marc Okrand
Power Klingon by Marc Okrand
Imperial Romulan Language Institute
Romulan Writing System on Omniglot
Central Institute of the Romulan Language
Romulan Language and Culture Institute
Romulan-English Dictionary
Romulan Language at Memory Alpha
Ferengi Language at Memory Alpha
Ferengi Writing System Part 1
Ferengi Writing System Part 2
The Bajoran Language File
Bajoran-English Dictionary
Bajoran Language at Memory Alpha
Trill Language at Memory Alpha
Trill Language at Holowiki (Not sure how accurate this is)
Dominionese at Memory Alpha
Borg Language at Memory Alpha
Andorian-English Dictionary
Andorian Language at Memory Alpha
Andorian Languages at Memory Beta