Bulgarian grammar is the grammar of the Bulgarian language. The Bulgarian language is a South Slavic language that also is one of the members of the Balkan sprachbund. As such, it shares several grammatical innovations with the other southwest Balkan languages that set it apart from other Slavic languages. These include a sharp reduction in noun inflections; most Bulgarian nouns and adjectives are inflected for number and gender, but have lost noun cases. Bulgarian also has a suffixed definite article, while most other Slavic languages have no definite article at all. Bulgarian has also lost the verb infinitive, while otherwise preserving most of the complexities of the Old Bulgarian verb conjugation system, and has further developed the proto-Slavic verb system to add verb forms to express nonwitnessed, retold, and doubtful (irrealis) actions. Bulgarian is a part of the Balkan linguistic union, which also includes Greek, Macedonian, Romanian, Albanian and Torlakian dialect of the Serbian language. Most of these languages share some of the above-mentioned characteristics.