Ekavian or ijekavian? The one vowel that splits Serbian down the middle

Order milk with breakfast in Belgrade and you will hear млеко. Order it in Nikšić, or in large parts of Bosnia, and you will hear млијеко - one extra syllable, same word, same grammar, same Serbian. Nobody in either city thinks the other one is speaking incorrectly. Both forms are standard, both are taught, and both trace back to a single Old Slavic vowel that the language quietly lost thirteen hundred years ago and has been improvising a replacement for ever since.

A vowel that stopped being pronounced but not written

Common Slavic had a vowel linguists write as ѣ (jat) - a sound distinct from both е and и, inherited into Old Church Slavonic and, through it, into every Slavic language's early written record. Russian kept a letter for it, ѣ, right up until the 1918 spelling reform, by which point it had merged in pronunciation with е and the letter was simply pruned as redundant. Serbian's story is more interesting, because the sound did not merge everywhere the same way - different regions resolved jat into three different, mutually incompatible outcomes, and all three are still spoken today.

Western dialects turned jat into и (this is ikavian, heard in parts of Croatia and Bosnia but not standardised for Serbian). The dialect Serbia's standard is built on turned it into a plain е - ekavian. A third, wider band running through Bosnia, Montenegro, Herzegovina and most of Croatia split jat in two depending on how long the vowel originally was: a long jat became the two-sound ије, a short jat became је - ijekavian, named for its own outcome the same way the other two are.

The Croatian city of Ријека is the mnemonic that makes this permanent: the name is simply the ijekavian word for river, spelled in Latin as Rijeka. The moment you can place that name, you can predict the ekavian counterpart of any word built the same way - река - without a dictionary.

Not a border between countries - a border inside Serbian

It is tempting to fold this into the wider Serbian/Croatian/Bosnian/Montenegrin naming split and stop there, but that undersells it: ekavian and ijekavian are both codified, official pronunciations of Serbian specifically, not one Serbian option and one foreign one. Serbia's own orthography names ekavian and ijekavian as its two parallel standard pronunciations. Serbs in Montenegro and in Bosnia's Republika Srpska write and speak standard Serbian in ijekavian as a matter of course, the same way an ekavian-speaking Serb in Belgrade does in ekavian - same declensions, same conjugations, same Serbian on the passport, different reflex of one vowel.

Serbian literature settles the point better than any rule could. Petar II Petrović-Njegoš, the Montenegrin bishop-prince whose epic Горски вијенац sits at the center of the Serbian literary canon, wrote it in ijekavian, because that was the speech of his own Montenegro. No Serbian reader treats the poem as written in a different language, or edits it into ekavian to belong on the shelf - ijekavian is not a guest dialect Serbian tolerates, it is one of the two forms Serbian comes in.

What this means if you are learning from this platform

This platform teaches ekavian, matching Serbia's own standard and the majority of what a beginner will read first. That is a starting point, not a ceiling: once the grammar underneath is solid, recognising the ijekavian form of a word you already know is a small, mechanical step - one vowel, in a predictable place, and every rule about cases, aspect and word order carries over unchanged. You are not learning a second dialect later. You are learning to notice one sound do a second job.