Gaj's Latin alphabet in the context of "Romanization of Serbian"

Bosnian is the standard variety of the Serbo-Croatian language mainly used by Bosniaks. It is one of the three official languages of Bosnia and Herzegovina; a co-official language in Montenegro; and an officially recognized minority language in Croatia, Serbia, North Macedonia and Kosovo.

Bosnian uses both the Latin and Cyrillic alphabets, with Latin in everyday use. It is notable among the varieties of Serbo-Croatian for a number of Arabic, Persian and Ottoman Turkish loanwords, largely due to the language's interaction with those cultures through Islamic ties.

In sociolinguistics, digraphia refers to the use of more than one writing system for the same language. Synchronic digraphia is the coexistence of two or more writing systems for the same language, while diachronic digraphia or sequential digraphia is the replacement of one writing system by another for a particular language.

Hindustani, with an Urdu literary standard written in Urdu alphabet and a Hindi standard written in Devanagari, is one of the "textbook examples" of synchronic digraphia, cases where writing systems are used contemporaneously. An example of diachronic digraphia, where one writing system replaces another, occurs in the case of Turkish, for which the traditional Arabic writing system was replaced with a Latin-based system in 1928.

The Serbian Cyrillic alphabet (Serbian: Српска ћирилица / Srpska ćirilica, IPA: [sr̩̂pskaː t͡ɕirǐlitsa]), also known as the Serbian script, (Српско писмо, Srpsko pismo, Serbian pronunciation: [sr̩̂psko pǐːsmo]), is a standardized variation of the Cyrillic script used to write Serbo-Croatian, namely its Serbian and Bosnian (mainly in Republika Srpska) standard varieties. It originated in medieval Serbia and was significantly reformed in the 19th century by the Serbian philologist and linguist Vuk Karadžić.

The Serbian Cyrillic alphabet is one of the two official scripts used to write modern standard Serbian, the other being Gaj's Latin alphabet. Karadžić based his reform on the earlier 18th-century Slavonic-Serbian script. Following the principle of "write as you speak and read as it is written" (piši kao što govoriš, čitaj kao što je napisano), he removed obsolete letters, eliminated redundant representations of iotated vowels, and introduced the letter ⟨J⟩ from the Latin script. He also created new letters for sounds unique to Serbian phonology. Around the same time, Ljudevit Gaj led the standardization of the Latin script for use in western South Slavic languages, applying similar phonemic principles.

Croatian is the standard variety of the Serbo-Croatian language mainly used by Croats. It is the national official language and literary standard of Croatia, one of the official languages of Bosnia and Herzegovina, Montenegro, the Serbian province of Vojvodina, the European Union and a recognized minority language elsewhere in Serbia and other neighbouring countries.

In the mid-18th century, the first attempts to provide a Croatian literary standard began on the basis of the Neo-Shtokavian dialect that served as a supraregional lingua franca – pushing back regional Chakavian, Kajkavian, and Shtokavian vernaculars. The decisive role was played by Croatian Vukovians, who cemented the usage of Ijekavian Neo-Shtokavian as the literary standard in the late 19th and the beginning of the 20th century, in addition to designing a phonological orthography. Croatian is written in Gaj's Latin alphabet.

Shtokavian or Štokavian (/ʃtɒˈkɑːviən, -ˈkæv-/; Serbo-Croatian Latin: štokavski / Serbo-Croatian Cyrillic: штокавски, pronounced [ʃtǒːkaʋskiː]) is the prestige supradialect of the pluricentric Serbo-Croatian language and the basis of its Bosnian, Croatian, Montenegrin and Serbian standards. It is a part of the South Slavic dialect continuum. Its name comes from the form for the interrogative pronoun for "what": što. This is in contrast to dialects that are exclusive to Croatian language: Kajkavian and Chakavian (kaj and ča also meaning "what").

Shtokavian is spoken in Bosnia and Herzegovina, the southern part of Austria's Burgenland, much of Croatia, Montenegro, Bosnia and Herzegovina and Serbia. The primary subdivisions of Shtokavian are based on three principles: one is different accents (whether the subdialect is Old-Shtokavian or Neo-Shtokavian), second is the way the old Slavic phoneme yat has changed (Ikavian, Ijekavian or Ekavian), and third is the presence of the Young Proto-Slavic isogloss (Schakavian or Shtakavian). Modern dialectology generally recognises seven Shtokavian subdialects.

The Royal Yugoslav Air Force (Serbo-Croatian Latin: Jugoslovensko kraljevsko ratno vazduhoplovstvo, JKRV; Serbo-Croatian Cyrillic: Југословенско краљевско ратно ваздухопловство, ЈКРВ; (Slovene: Jugoslovansko kraljevo vojno letalstvo, JKVL); lit. "Yugoslav royal war aviation"), was the aerial warfare service component of the Royal Yugoslav Army (itself the land warfare branch of the Kingdom of Yugoslavia). It was formed in 1918 and existed until 1941 and the Invasion of Yugoslavia during World War II.

Some 18 aircraft and several hundred aircrew escaped the Axis invasion of April 1941 to the Allied base in Egypt, eventually flying with the Royal Air Force in the Northern Africa initially and then with the Balkan Air Force in Italy and Yugoslavia, with some even going on to join the Soviet Air Force, returning to Yugoslavia in 1944.