as Italian, Spanish, French and Portuguese. Compared with the other Romance languages, the closest relative of Romanian is Italian. Romanian has had a greater share of foreign influence than some other Romance languages such as Italian in terms of vocabulary and other aspects. A study conducted by Mario Pei in 1949 which analyzed the degree of differentiation of languages from their parental language (in the case of Romance languages to Latin comparing phonology, inflection, discourse, syntax, vocabulary, and intonation) produced the following percentages (the higher the percentage, the greater the distance from Latin): Sardinian: 8% Italian: 12% Spanish: 20% Romanian: 23.5% Occitan: 25% Portuguese: 31% French: 44% The lexical similarity of Romanian with Italian has been estimated at 77%, followed by French at 75%, Sardinian 74%, Catalan 73%, Portuguese and Rhaeto-Romance 72%, Spanish 71%. The Romanian vocabulary became predominantly influenced by French and, to a lesser extent, Italian in the nineteenth and early twentieth centuries. Balkan language area While most of Romanian grammar and morphology are based on Latin, there are some features that are shared only with other languages of the Balkans and not found in other Romance languages. The shared features of Romanian and the other languages of the Balkan language area (Bulgarian, Macedonian, Albanian, Greek, and Serbo-Croatian) include a suffixed definite article, the syncretism of genitive and dative case and the formation of the future and the alternation of infinitive with subjunctive constructions. According to a well-established scholarly theory, most Balkanisms could be traced back to the development of the Balkan Romance languages; these features were adopted by other languages due to language shift. Slavic influence Slavic influence on Romanian is especially noticeable in its vocabulary, with words of Slavic origin constituting about 10–15% of modern Romanian lexicon, and with further influences in its phonetics, morphology and syntax. The greater part of its Slavic vocabulary comes from Old Church Slavonic, which was the official written language of Wallachia and Moldavia from the 14th to the 18th century (although not understood by most people), as well as the liturgical language of the Romanian Orthodox Church. As a result, much Romanian vocabulary dealing with religion, ritual, and hierarchy is Slavic. The number of high-frequency Slavic-derived words is also believed to indicate contact or cohabitation with South Slavic tribes from around the 6th century, though it is disputed where this took place (see Origin of the Romanians). Words borrowed in