About Serbian
Serbian is a standardized form of the Shtokavian dialect of Serbo-Croatian used as an official language of Serbia, Bosnia and Herzegovina, and Kosovo. The same subdialect of Shtokavian is also the basis for the mutually intelligible standards of Croatian, Bosnian, and Montenegrin. Indeed, in Bosnia and Herzegovina, "Croatian", "Bosnian", and "Serbian" are considered to be three names for the same official language.

Before 1400, most Serbian vernaculars had two accents, both with fall intonation—the short one and the long one. That is why they are called "old accents". By 1500, the old accents moved by one syllable towards the beginning of the word, changing their quality to rising accents.

Most of the words in Serbian are of Slavic origin. That means that their roots continue some words reconstructed for Proto-Slavic language.

source: Serbian