Serbia's other alphabet was designed by a Croat, for a different language
Vuk Karadžić spent the 1810s and 1820s rebuilding Serbian Cyrillic so every letter meant exactly one sound. The Latin alphabet Serbian also uses today was built the same decades, for a different language, by a Croatian journalist who never set out to write Serbian at all - and the reason the two ended up sharing one language is a story about an empire, not an alphabet.
The previous article on this blog left one thread hanging: why does Serbian have two fully official alphabets in the first place, when most languages that switched scripts simply switched once? The short answer pointed at borders, empires and churches and moved on. Here is the part that was skipped - and it starts with a man who was not Serbian, writing for a language that was not quite Serbian either.
A movement, not a language reform
In the 1830s, in the Croatian lands of the Habsburg Empire, a young journalist named Ljudevit Gaj led what became known as the Illyrian movement: an attempt to build a shared South Slavic literary identity - Croats, Serbs, Slovenes and others together - partly as a defence against Hungarian political and linguistic pressure inside the same empire. A shared identity needed a shared way of writing, and Gaj set out to give Croatian, which was already written in Latin letters, a spelling that actually matched how it sounded.
Before Gaj, Croatian Latin spelling borrowed its extra sounds from Hungarian conventions - the sound Serbian writes with a single letter ч might appear as cs, and ж as zs - readable, but inconsistent and foreign-looking on the page. Gaj's 1830 proposal replaced these with diacritics borrowed from Czech spelling - č, ž, š - giving Croatian, for the first time, one clean sign per sound. It is the same problem Vuk was solving for Cyrillic in the very same years, one border over, for reasons that had nothing to do with each other.
One agreement, two alphabets
The Illyrian movement's grander political goal did not survive the century, but it left behind one lasting document: in 1850, a group of Croatian and Serbian writers meeting in Vienna - including Vuk himself - agreed on a shared literary standard for what they called one language spoken by two peoples, based squarely on Vuk's own reformed grammar. The agreement settled the grammar and the sound system, not the alphabet: Serbs would go on writing that shared language in Vuk's Cyrillic, and Croats in Gaj's Latin. Two scripts for one standard stopped being a problem to solve and simply became the arrangement.
The one letter Gaj's alphabet was missing
Gaj's alphabet was built for Croatian, and Croatian did not lean on one particular sound as heavily as Serbian did: the hard џ, common in Serbian through centuries of contact with Turkish. Đuro Daničić - Vuk's closest collaborator and the philologist most responsible for turning Vuk's reform into a lasting standard - is generally credited with the fix that finished the correspondence: a distinct digraph, dž, kept apart from đ so the two sounds could never be confused on the page. With that one addition, Gaj's Latin alphabet matched Vuk's Cyrillic letter for letter, sound for sound.
Она је најбољи ђак у разреду.
She is the best pupil in the class.
Ђак - the letter Daničić did not need to touch.
Носи књигу у џаку.
He's carrying a book in a sack.
Џак differs from ђак by exactly the sound Daničić's letter keeps distinct - the two words are otherwise identical in shape.
Neither reformer thought of the result as designing an alphabet for Serbian and Croatian to share - that outcome followed from a political agreement made twenty years after Gaj's proposal, and was driven by Habsburg politics far more than by linguistics. The alphabets converged before anyone decided the languages should.
The practical result for a learner today has nothing to do with any of this politics: гајица is not a foreign import bolted onto Serbian, and reading it costs a Russian speaker roughly the fifteen minutes the other article on this blog already promised - twenty-two letters you already have, five diacritics, three digraphs, and one small piece of history behind every one of them.