The Yarphese language was created by Trầng Chúp Long for use in the Grand Yarphese Republic. It has become a mainstream language due to its extremely simple grammar. It is taught in almost most Yarphese schools now, but the fluent population is only about 12 million speakers. It is the main government language of Yarphei. The Yarphese Pledge is sung in Yarphese only.
Tranh created the language in order to unify his young country. The languages ranged from Vietnamese in the north to Malay in the south. His first idea was to create an intermediate language. However, he dropped this plan when he discovered how inefficient such a language would be in terms of syllables. As a supporter of the Sapir-Whorf Hypothesis, he also despised English at the time, calling it a barrier to logical thinking. He decided he would create a language based off one of his mother tongues, Vietnamese. In order to increase literacy, he created the language to be very simple, but with thousands of words to speed up thought and communication.
The language is quite simple, with only two parts of speech. Each word comprises exactly one syllable, similar to Vietnamese. In order to increase efficiency, there are several vowels and tones. The language has been criticized since ambiguity may result, but it has caused little trouble among the fluent population. A unique aspect of the language is the use of aspects, describing the stage in time of a given object or verb. This results in very lengthy translations of what appear to be short sentences in Yarphese.
The current writing system is the Latin alphabet. However, there are many quirks in the writing system. While the orthography is based somewhat off the Vietnamese system of writing, there are also strange uses of consonants and vowels, giving the language an often Celtic appearance. Long has mentioned that the purpose of these spelling rules is to give Yarphei a unique national identity.
Yarphese is employed as a teaching aid for grammar and pronunciation in schools. It is also a patriotic language, and being able to speak Yarphese is considered an excellent show of patriotism and helps in job interviews. Occasionally corporations use it for trademarked names. Finally, the Yarphese Pledge is sung in Yarphese only.
Vietnamese was traditionally a main language of the Yarphese government and the language of the original Vietnamese Liberation Army. However, in 1999, at the rise of the military junta, Trầng Chúp Long declared that Yarphese Vietnamese (Tıến Yậtphờı or Tiếng Viẹt Phời) would replace Yarphese as the national language on the following grounds:
- Yarphei has become the New Vietnam and should embrace its culture.
- Vietnamese was the official language of the VLA, and was only replaced to give Yarphese a national identity, which has been accomplished.
- Vietnamese is applicable around the world among Vietnamese speaker.
- Yarphei already has a sizeable number of Vietnamese speakers.
- Yarphese was implemented for the purpose of allowing children to learn more languages—children who are now able to speak the languages will be able to pass them on to the next generations.
- Vietnamese is already implemented in Vietnam and will save money printing signs and books.
The Yarphese Dialect was designed by Phang Yăng Huông (Phan Văn Huông) in a competition with 136 entries on simplification of the Vietnamese language. It was chosen on the following ideas:
- Condensation of monosyllables into words rather than using hyphens, allowing better computer parsing.
- Changes in spelling to reflect a modified Saigon dialect, ensuring one-to-one written/oral correspondence.
- Pronunciation is simplified slightly to ensure coherence.
- Dots are removed from is.
- Certain common words are abbreviated, such as con to c.
- Sự and Phı are changed into prefixes s- and p-.
- Vocabulary is edited negligibly to encourage the use of Vietnamese words over Sino-Vietnamese words and Southern Vietnamese words over Northern Vietnamese words.
- A large variety of toponyms are used to rename Yarphese places.
English is the most common language used in Yarphei next to Vietnamese. It is frequently used in speeches by leaders, and was the first language of the Vietnamese Liberation Army. In 2003, a dialect of English based on Australian, Vietnamese, and Singaporean English emerged. The dialect has been considered unique and has been described by speakers of Received Pronunciation as Australian with traces of Vietnamese.
French is now widely being introduced into the Yarphese curriculum as an alternative to English. It is slowly gaining prominence and already has enthusiast communities throughout Yarphei.
Due to tensions with Thailand and among those living Yarphei's northern Thai provinces, Southern Thai has been the standard for pronunciation since 1996. It is a common working language.
Khmer was standardized in 2003. It remains one of Yarphei's major languages.
Chinese languages are common. Like one of its predecessors, Singapore, Yarphei has promoted Mandarin as the standard Chinese dialect, but is slowly being replaced by Vietnamese.