Alison Baird
The Dragon Throne series: The Stone of the Stars , The Empire of the Stars , The Archons of the Stars
[Elensi, Zimbouran, Kaanish]
Includes good language notes, especially for Elensi.

David Brin
Uplift Saga: Sundiver , Startide Rising , The Uplift War .
Uplift Trilogy: Brightness Reef , Infinity's Shore , Heaven's Reach
[Galactic One through Twelve, Anglic, Neo-Dolphin, etc.]
The universe of the Uplift has been summarized in the following book: Brin, David and Kevin Lenagh. Contacting Aliens: An Illustrated Guide to David Brin's Uplift Universe . (New York: Bantam Spectra, 2002).

Edward Bulwer-Lytton
The Coming Race
This novel was first published anonymously in 1871. The universal language movement of the time is evident: By a single letter, according to its position, they contrive to express all that with civilised nations in our upper world it takes the waste, sometimes of syllables, sometimes of sentences, to express. Let me here cite one or two instances: An (which I will translate man), Ana (men); the letter 's' is with them a letter implying multitude, according to where it is placed; Sana means mankind; Ansa, a multitude of men. There is a Google Books online version of the book. It is also available full-text from Project Gutenberg

Anthony Burgess
A Clockwork Orange
[Nadsat]
The book is actually written in Nadsat, which one learns as the story unfolds. Burgess did an amazing job in incorporating the teen "slanguage" into the narrative.

Edgar Rice Burroughs
Martian Tales: A Princess of Mars , Gods of Mars , Warlord of Mars , Thuvia, Maid of Mars , Chessmen of Mars , The Master Mind of Mars , A Fighting Man of Mars , Swords of Mars , Synthetic Men of Mars , Llana of Gathol , John Carter of Mars
Barsoomian (Martian)]
Burroughs populates the Red Planet (whose native name is Barsoom) with an interesting array of native species including the towering four-armed Green Men (the Thark). Each race of beings is given their own distinctive sounding names and words. Several of these works are also available in full text at Project Gutenberg under Burroughs as well as several other full text databases on the Internet.

Orson Scott Card
The Homecoming Saga: The Memory of Earth , The Call of Earth , The Ships of Earth , Earthborn , Earthfall
[Human languages of the planet Harmony]
Interesting naming conventions are explained and pronunciation guides are given in several of the volumes. The series is loosely patterned after the Book of Mormon. Several of the books have good languages notes and glossaries.

C. J. Cherryh
The Chanur Saga (includes The Pride of Chanur, Chanur's Venture, and The Kif Strike Back). Also in the series: Chanur's Homecoming , Chanur's Legacy
[Hani, Kiffish]

C. J. Cherryh
The Foreigner Universe series: Foreigner , Invader , Inheritor , Precursor , Defender , Explorer , Destroyer , Pretender , Deliverer , Conspirator , Deceiver , Betrayer
[Atevi]
Cherryh does an excellent job of populating her novels with interesting alien species, along with appropriate alien languages. Several of the books in these two series include pronunciation guides and glossaries.

Ted Chiang
"The Story of Your Life"
[Heptapod A and B]
Short story appearing in Chiang's anthology Stories of Your Life and Others

L. Sprague de Camp
Years in the Making: The Time-Travel Stories of L. Sprague de Camp
[various]
Several entries in this collection involve conlanging including the short story "The Wheels of If" and the essay "Language for Time Travelers".

Samuel R. Delany
Babel-17
[Babel-17 (takes a Sapir-Whorfian view of language)]

Suzette Haden Elgin
Native Tongue Trilogy: Native Tongue , The Judas Rose , Earthsong
[Láadan - a language constructed by women in a male-dominated society but designed for use by all people]
Elgin has also published A First Dictionary and Grammar of Láadan: Second Edition (1988). The author is a proponent of the Sapir-Whorf hypothesis and constructed Láadan to demonstrate the effects of this on her characters.

Sheila Finch
The Guild of Xenolinguists
[various alien language concepts - not full languages]
Finch does not include actual alien languages within this collection of connected short stories, but she does an excellent job of giving a good idea of what being a xenolinguist (or 'lingster') would be like from the perspective of various members of the Guild. Finch has also written several other novels/novellas featuring the Guild: Reading the Bones , Birds , and Triad . Reading the Bones was the 1998 Nebula novella award winner.

Eric Flint & K.D. Wentworth
The Course of Empire
[Jao]
The intricate naming conventions of the Jao are explained in the preface.

Percy Greg
Across the Zodiac: The Story of a Wrecked Record
This novel, published in 1880, is considered by some to be the originator of the sword and planet sub-genre of science fiction. One can also see an influence from the popular 19th-century universal language movement in this excerpt: I soon found that, unlike any Terrestrial tongue, the language of this people had not grown but been made--constructed deliberately on set principles, with a view to the greatest possible simplicity and the least possible taxation of the memory. There is a Google Books online version of the book. It is also available full-text from Project Gutenberg

Harry Harrison
West of Eden series: West of Eden , Winter in Eden , Return to Eden
[Yilané, Marbak, Sesek, Angurpiaq]
Harrison's intelligent lizard and human races are well developed. The necessity of learning one's captor's language is a major part of the story in West of Eden. Language notes and glossaries are included in the volumes.

Frank Herbert
Dune: The original series encompasses a trilogy - Dune , Dune Messiah , Children of Dune
[Fremen, Chakobsa, Galach]
Herbert provides snippets of conlangs throughout his works. John Quijada co-wrote an extensive article in the Dune Encyclopedia on the Fremen language, including a script.

Russell Hoban
Riddley Walker
["Riddleyspeak"]
This post-apocalyptic novel is written entirely in the speech of the narrator. An often overlooked masterpiece of conlang fiction, comparing favorably to A Clockwork Orange .

Antony Johnston (writer) and Christopher Mitten (artist)
Wasteland series
["Sandeater"]
This "post-apocalyptic western" comic book series includes a distinct future English dialect for its Sandeaters (e.g., STILLA STRONNN. NAHSTRONNINAAA. means Still strong. Not strong enough.).

Ursula K. LeGuin
Always Coming Home
[Kesh]
A well-developed set of language notes on Kesh accompanies this work.

Ursula K. LeGuin
The Left Hand of Darkness
[Gethenian]

C. S. Lewis
Out of the Silent Planet
[Malacandran]
This is the first book in Lewis' Space Trilogy. The other titles are Perelandra and That Hideous Strength . Lewis' protagonist, Elwin Ransom, is a professor of philology.

Barry Longyear
The Enemy Papers
[Drac]
This anthology includes the short stories "Enemy Mine," "The Last Enemy," and "The Tomorrow Testament," as well as "The Talman" (the Drac "Bible"), "On Alien Languages," "Run Drac Run," and "Drac for Travelers." An excellent comprehensive review of the anthology is available here.

Frederick Spencer Oliver
A Dweller on Two Planets or, The Dividing of the Way
[Atlantean or Poseid language]
This novel, first published in 1894, purports to be the biography of the author's past live as an Atlantean names Phylos. There is a Google Books online version of the book.

H. Beam Piper
The Complete Fuzzy
[Gashta]
This anthology includes "Little Fuzzy," "Fuzzy Sapiens," and "Fuzzies And Other People." The first story centers around the controversy of whether the "Fuzzies" are sapient, and hinges on whether they use language. William Tuning's Fuzzy Bones (1981) and Ardath Mayhar's Golden Dream: A Fuzzy Odyssey (1982) were official sequels to Piper's works. Golden Dream has a nice glossary of Gashta.

H. Beam Piper also wrote "Omnilingual", a short story appearing in the anthology From Mind to Mind: Tales of Communication from Analog . The story revolves around the efforts to translate the Martian language from magazines found in archaeological digs on the Red Planet.

Nina Post (with David J. Peterson)
The Zaanics Deceit
[Væyne Zaanics]
From Nina Post's website: The Zaanics Deceit includes "a constructed language with its own grammar and lexicon. Inspired by Latin, Middle English and Old French, the language was designed to be passed on from generation to generation within the Lyr and Severn families, and plays a prominent role within the fictional universe of the series." David J. Peterson mentions Væyne Zaanics in this interview and in his book, The Art of Language Invention.

Diane Reed Slattery
The Maze Game
[Glide]

Heather Spears
The Moonfall Trilogy : Moonfall, The Children of Atwar, The Taming
[Riksprok (a future Scandinavian language)]
More on Spears' science fiction can be found at her website: www.heatherspears.com/contents/scifi.htm

Lorinda Taylor
The Termite Queen
[Shshi]
Lorinda Taylor has written a story of a true alien civilization comprised of intelligent termites. Her Conlangs of a Remembrancer blog provides details of their language (as well as other conlangs Taylor is working on). Her Ruminations of a Remembrancer provides more details about her work.

Amy Thomson
The Color of Distance
[Tendu skinspeech]
"Speakers" of Tendu employ changing colors and patterns on their skin to communicate, a novel concept for conlangs. As for things to be aware of when recommending The Color of Distance, the protagonist mentions being raped when younger; alien mating rituals are described, as is a human sexual encounter (explicitly). The story continues in Thomson's sequel Through Alien Eyes .

Jack Vance
The Languages of Pao
[Paonese, Breakness, Mercantile, etc.]

Ian Watson
The Embedding
[explores Noam Chomsky's theory of "innateness"]