Bulgarian grammar is the grammar of the Bulgarian language. Bulgarian is a South Slavic language that evolved from Old Church Slavonic—the written norm for the Slavic languages in the Middle Ages which derived from Proto-Slavic. Bulgarian is also a part of the Balkan sprachbund, which also includes Greek, Macedonian, Romanian, Albanian and the Torlakian dialect of Serbian. It shares with them several grammatical innovations that set it apart from most other Slavic languages, even other South Slavic languages. Among these are a sharp reduction in noun inflections—Bulgarian has lost the noun cases but has developed a definite article, which is suffixed at the end of words. In its verbal system, Bulgarian is set apart from most Slavic languages by the loss of the infinitive, the preservation of most of the complexities of the older conjugation system (including the opposition between aorist and imperfect) and the development of a complex evidential system to distinguish between witnessed and several kinds of non-witnessed information. Bulgarian nouns Bulgarian nouns have the grammatical gender, number (including count form), definiteness and vocative form. A noun has one of three specific grammatical genders (masculine, feminine, neuter). A noun has two numbers (singular and plural), plus a numerical plural form. The plural is formed by adding to or replacing the singular ending, most commonly in the following ways: With cardinal numbers and some adverbs, masculine nouns use a separate numerical plural form бройна множествена форма (broyna mnozhestvena forma). It is a vestige of the grammatical dual number, which disappeared from the language in the Middle Ages. The numerical form is used in the masculine whenever there is a precise amount of something, regardless of the actual number, e.g. – стол (stol "chair") → много столове (mnogo stolove "many chairs", general plural) → два стола / десет стола (dva stola / deset stola "two chairs / ten chairs", numerical plural).