Romulan

Romulan (Rihan) is a fictional language in the Star Trek non-canon universe. In its fictional context it is spoken by the Romulans and Remans. It was developed by science fiction writer Diane Duane for her Rihannsu novel series set in the Original Series time period and has been expanded by fans in the years since.

The language has also appeared in the Star Trek: Enterprise continuation novels (notably the Romulan War series), and in the MMORPG Star Trek Online.

History
Diane Duane debuted several sentences and words from Rihan in her first Star Trek novel, My Enemy, My Ally. This became the first book in a five-novel series called Rihannsu, which included a partial glossary. Duane also pitched a full Romulan dictionary to go along with Marc Okrand's The Klingon Dictionary, but it was never published.

In The Romulan Way, Rihan is said by an in-universe historian to have been developed by the proto-Romulans, dissidents from the Vulcan luminary Surak's philosophies, as a deliberate conlang (akin to Esperanto in real-life) by going back to classical Old High Vulcan and "aging" the language in a different direction.

In canon
In canon Star Trek, the Romulan language is used much less than other languages seen in the show. It is completely undeveloped, and does not even have a name for itself or its speakers in the actual show.

Characteristics
Rihan uses features similar to many Romance languages, particularly Latin. Clauses are conventionally ordered subject-verb-object, and nouns have three declination cases based on position and purpose in the sentence (adjectives are also declined and agree with the corresponding noun in number and case). Speakers may alternatively use a verb-object-subject word order.

The verb "to be" is expressed by affixing the prefix "ahr'" to either the adjective or the second noun in a given statement.

Words often use an "ae" diphthong, which may be expressed with the æ character and is pronounced as a short 'a', as in "Jack".

Words & Phrases

 * deihu = usually translated as "senator", in actual fact a noble title closer to "clan leader". These serve as legislators.
 * Deihuit = the Romulan Senate
 * fvillha = usually translated as "praetor", in actual fact a noble title closer to "lands-master". In the Rihannsu novel series, the fvillhar (numbering about twelve) formed the Praetorate, a higher house of the Romulan legislature the Tricameron. In the 24th century TV shows and Star Trek Online, a single praetor served the role of a prime minister in the Romulan government.
 * galae = usually translated as "fleet", such as a space navy, but has connotations more akin to aircraft squadrons than aquatic naval forces, hearkening back to the adoption of massed airpower in historical Romulan internal wars
 * Jolan'tru = A commonly used greeting
 * Khe'lloann'mnhehoræl = slang term for the Klingon Empire, literally "more of them, from somewhere else"
 * Khe'lloann'na = slang term for a Klingon (pl. "Khe'lloann'nasu", adj. "Khe'lloann")
 * Klivam = derogatory term for a Klingon (pl. "Klivammsu")
 * Klling'hannha = formal term for a Klingon (pl. "Klling'hannsu", adj. "Klling'hann")
 * Klling'hann Nneikha = formal name for the Klingon Empire
 * kheh'irho = Romulan ale, literally "kheh drink" (kheh being a type of grain).
 * Havrannsu = Remans (sing. "Havranha"), literally "the Travelers"
 * ch'Havran = the planet Remus, literally "(planet) of the Travelers"
 * lleiset = freedom
 * Lloann'mhrahel = slang term for the United Federation of Planets, literally "them, from there"
 * Lloann'na = a Federation citizen (pl. "Lloann'nasu")
 * Lloannen'galæ = the Federation Starfleet
 * mnhei'sahe = literally "the Ruling Passion", the Romulan concept of honor. Comprises a combination of clan and family honor, personal integrity and "face", and enlightened self-interest: to wit, while a Romulan is expected to be thinking of their own good first and foremost, their actions should still bring benefit to those affected by them.
 * Rihannsu = Romulans (sing. "Rihanha"), literally "the Declared"
 * ch'Rihan = the planet Romulus, literally "(planet) of the Declared"
 * Rihan = adjective, "of or relating to Romulans"
 * Rihanh = the Romulan people
 * riov = "commander", military rank equivalent to a Starfleet captain
 * erei'riov = "subcommander", military rank equivalent to a Starfleet commander
 * khre'riov = "commander general" or "subadmiral", military rank equivalent to a Starfleet commodore or rear admiral
 * Shiar ih'Saeihr Rihan = the Romulan Star Empire. Note that "shiar" is a word exclusively used for an empire of Romulans; the generic translation of "empire" is "nneikha", e.g. "Klling'hann Nneikha" for the Klingon Empire.