Indonesian orthography refers to the official spelling system used in theIndonesian language. The current system uses theLatin script and is calledEjaan yang Disempurnakan (EYD), commonly translated asEnhanced Spelling,Perfected Spelling orImproved Spelling.^[1][2][3][4]

The Perfected Spelling system is a system of orthography released in 1972 to replace the preexistingRepublican Spelling System (RSS, also called the Soewandi Spelling System,SSS). A joint initiative of Indonesia and neighboring countryMalaysia (which also introduced the similarJoint Rumi Spelling system), the aim of the change in 1972 was to introduce greater harmonization of theIndonesian and Malay-language orthographies. The new EYD system, adopted on the 27th anniversary of Indonesia's independence on 17 August 1972, was decreed by PresidentSuharto on the previous day.^[5] Government departments were instructed to begin using the EYD system on 1 January 1973. On 27 August 1975, theMinister of Education and Culture issued a decree which provided a detailed explanation of the changes in the new system and marked the official use of the EYD system.^[6] It was formerly known as theIndonesian Spelling System (Ejaan Bahasa Indonesia,EBI), often referred to as theIndonesian Spelling System General Guidelines (Pedoman Umum Ejaan Bahasa Indonesia,PUEBI), between 2015 and 2022.^[3]

Letters that had previously been included in the Republican Spelling as foreign loan letters are officially used in the EYD Spelling.^[7]

The letters Q and X are used in scientific subjects,^[7] for examplesinar-X (X-ray).

The letter Q is also used as needed for Islamic subjects.^[8][9] Examples includeQuran,Al-Furqan, andAl-Baqarah. This letter is also used in some placenames in Indonesia (often derived from the local languages), e.g. theSiluq Ngurai [id] andSekolaq Darat [id] districts inWest Kutai Regency, and Baqa, the capital ofSamarinda Seberang,Samarinda (all of these examples are located inEast Kalimantan).

The writing ofdi- andke- (prefixes) can be distinguished fromdi andke (prepositions), wheredi- andke- are written together with the words that follow them, for examplediambil,kehendak ('taken', 'desire'), whiledi andke are written separately from the words that follow them, for exampledi rumah,ke pasar ('at home', 'to the market'). This is different from the former Republican Spelling, where bothdi- anddi are written together with the words following them.^[7] However, many native speakers often do not follow this orthographic rule, and confuse both morphemes (di ambil,dirumah).

Dutch linguistK. Alexander Adelaar viewed that the prefixdi- derives instead from the prepositiondi, and rejected other etymological theories, such as it coming from theOld Malay prefixni-.^[10]

Reduplication, mostly used in the plural form of words, has to be fully written with letters, so the use of asuperscripted number2 as in the Republican Spelling is no longer valid.^[7] The practice remains common in informal usage such as in text messaging.

Exceptions mostly come from proper nouns. Many personal names, particularly of younger people, do not follow the orthographic rules (seeIndonesian names). Common spelling variations include doubled letters, asilenth following consonants, the use ofDutch digraphs (which stems fromVan Ophuijsen spelling),^[11] and other eccentric letters.^[12] However, a few variations come from other parts of speech, such asmag ('gastritis') which is actually pronounced as[max] or even[mah], deriving from Dutchmaag; andbus, pronounced as[bəs] or[bɪs], also from Dutchbus.

Various minor changes were announced after 1975:

• On 9 September 1987, the Minister of Education and Culture issued a ministerial decree^[13] which updated the previous spelling system and remained valid for 22 years.
• On 31 July 2009, the Minister of National Education issued a decree outlining further changes.^[14] The update included an optionaldiacritic for ⟨e⟩, to distinguish ⟨é⟩[e] and ⟨e⟩[ə].
• On 26 November 2015, the Minister of Education and Culture issued a ministerial regulation about the spelling system.^[15] For the first time, the termIndonesian spelling system was used. There were only minor changes compared to previous updates, including the addition of a newdiphthong of ⟨ei⟩ (previously there were only 3 diphthongs,ai,au andoi), optionaldiacritics for ⟨e⟩ as ⟨é⟩[e], ⟨è⟩[ɛ], and ⟨ê⟩[ə], and new rules on the usage of bold letters (abolition of bold letters forlemma entries in its dictionary).
• On 16 August 2022, in time for the spelling system's fiftieth anniversary, a new update for it was issued.^[16] It restored the termPerfected Spelling of the Indonesian Language (Ejaan Bahasa Indonesia yang Disempurnakan). Like the previous update, it also introduced minor changes: among others, it introduced themonophthong ⟨eu⟩[ɘ], mostly used in loanwords fromAcehnese andSundanese, reaffirmed the use of the optional diacritic ⟨ê⟩[ə], and limited the use ofnumber words to singular numbers.^[16]

• New Rumi Spelling
• Republican Spelling System
• Van Ophuijsen Spelling System

• Official website for the fifth edition of EYD

• Indonesian language
• Spelling reform
• Latin-script orthographies

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• CS1: long volume value
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