Standard Romanian (i.e. the Daco-Romanian language within Balkan Romance) shares largely the same grammar and most of the vocabulary and phonological processes with the other three surviving varieties of Balkan Romance, namely Aromanian, Megleno-Romanian, and Istro-Romanian. As a Romance language, Romanian shares many characteristics with its more distant relatives: Italian, French, Spanish, Portuguese, Catalan, etc. However, Romanian has preserved certain features of Latin grammar that have been lost elsewhere. This could be explained by a host of arguments such as: relative isolation in the Balkans, possible pre-existence of identical grammatical structures in its substratum (as opposed to the substrata over which the other Romance languages developed), and existence of similar elements in the neighboring languages. One Latin element that has survived in Romanian while having disappeared from other Romance languages is the morphological case differentiation in nouns. Nevertheless, declensions have been reduced to only three forms (nominative/accusative, genitive/dative, and vocative) from the original six or seven. Another might be the retention of the neuter gender in nouns, although in synchronic terms, Romanian neuter nouns can also be analysed as "ambigeneric", that is as being masculine in the singular and feminine in the plural (see below) and even in diachronic terms certain linguists have argued that this pattern, as well as that of case differentiation, was in a sense "re-invented" rather than a "direct" continuation of the Latin neuter. Romanian is attested from the 16th century. The first Romanian grammar was Elementa linguae daco-romanae sive valachicae by Samuil Micu and Gheorghe Șincai, published in 1780. Many modern writings on Romanian grammar, in particular, most of those published by the Romanian Academy (), are prescriptive; the rules regarding plural formation, verb conjugation, word spelling and meanings, etc. are revised periodically to include new tendencies in the language. Nouns Gender Romanian nouns are categorized into three genders: masculine, feminine, and neuter. The neuter behaves like the masculine in the singular and the feminine in the plural, unlike the neuter in Latin which had distinct forms. Nouns which in their dictionary form (singular, nominative, with no article) end in a consonant or the vowel/semivowel -u are mostly masculine or neuter; if they end in -ă or -a they are usually feminine. In the plural, the ending -i corresponds generally to masculine nouns, whereas feminine and neuter nouns often end in -e. As there are many exceptions to these rules, each noun must be learned