Scientific transliteration, variously called academic, linguistic, international, or scholarly transliteration, is an international system for transliteration of text from the Cyrillic script to the Latin script (romanization). This system is most often seen in linguistics publications on Slavic languages.
Scientific transliteration of Cyrillic Wikipedia
The scientific transliteration system is roughly as phonemic as is the orthography of the language transliterated. The deviations are with щ, where the transliteration makes clear that two phonemes are involved, and џ, where it fails to represent the (monophonemic) affricate with a single letter. The transliteration system is based on the Gaj's Latin alphabet used in Serbo-Croatian, in which each letter corresponds directly to a Cyrillic letter in Bosnian, Montenegrin and Serbian official standards, and was heavily based on the earlier Czech alphabet. It was codified in the 1898 Prussian Instructions for libraries, or Preußische Instruktionen (PI). It can also be used to romanize the early Glagolitic alphabet, which has a close correspondence to Cyrillic.
Scientific transliteration is often adapted to serve as a phonetic alphabet.
Scientific transliteration was the basis for the ISO 9 transliteration standard. While linguistic transliteration tries to preserve the original language's pronunciation to a certain degree, the latest version of the ISO standard (ISO 9:1995) has abandoned this concept, which was still found in ISO/R 9:1968 and is now restricted to a one-to-one mapping of letters. It thus allows for unambiguous reverse transliteration into the original Cyrillic text and is language-independent.
The previous official Soviet romanization system, GOST 16876-71, is also based on scientific transliteration but used Latin h for Cyrillic х instead of Latin x or ssh or sth for Cyrillic Щ and had a number of other differences. Most countries using Cyrillic script now have adopted GOST 7.79 instead, which is not the same as ISO 9 but close to it.
Representing all of the necessary diacritics on computers requires Unicode, Latin-2, Latin-4, or Latin-7 encoding.*
Letters in parentheses are older or alternate transliterations.
No longer actual in Bulgaria; superseded by the official Streamlined System made mandatory for common use in a law of 2009, and endorsed for official use by UN in 2012, and by the USA and the United Kingdom in 2013.
Ukrainian and Belarusian apostrophe are not transcribed. The early Cyrillic letter koppa (Ҁ, ҁ) was used only for transliterating Greek and its numeric value and was thus omitted. ISO 9:1995 is provided for comparison.