Balkan-Romance is represented by Romanian and its historical dialects: Daco-Romanian (broadly known as Romanian), Aromanian, Megleno-Romanian, and Istro-Romanian (see article “Morphological and Syntactic Variation and Change in Romanian” in this encyclopedia). The external history of these varieties is often unclear, given the historical events that took place in the Lower Danubian region: the conquest of this territory by the Roman Empire for a short period and the successive Slavic invasions. Moreover, the earliest preserved writing in Romanian only dates from the 16th century. Between the Roman presence in the Balkans and the first attested text, there is a gap of more than 1,000 years, a period in which Romanian emerged, the dialectal separation took place, and the Slavic influence had effects especially on the lexis of Romanian. In the 16th century, in the earliest old Romanian texts, the language already displayed the main features of modern Romanian: the vowels /ə/ and /ɨ/; the nominative-accusative versus genitive-dative case distinction; analytical case markers, such as the genitive marker al; the functional prepositions a and la; the proclitic genitive-dative marker lui; the suffixal definite article; polydefinite structures; possessive affixes; rich verbal inflection, with both analytic and synthetic forms and with three auxiliaries (‘have’, ‘be’, and ‘want’); the supine, not completely verbalized at the time; two types of infinitives, with the ‘short’ one on a path toward becoming verbal and the ‘long’ one specializing as a noun; null subjects; nonfinite verb forms with lexical subjects; the mechanism for differential object marking and clitic doubling with slightly more vacillating rules than in the present-day language; two types of passives; strict negative concord; the SVO and VSO word orders; adjectives placed mainly in the postnominal position; a rich system of pronominal clitics; prepositions requiring the accusative and the genitive; and a large inventory of subordinating conjunctions introducing complement clauses. Most of these features are also attested in the trans-Danubian varieties (Aromanian, Megleno-Romanian, and Istro-Romanian), which were also strongly influenced by the various languages they have entered in direct contact with: Greek, Albanian, Macedonian, Croatian, and so forth. These source languages have had a major influence in the vocabulary of the trans-Danubian varieties and certain consequences in the shape of their grammatical system. The differences between Daco-Romanian and the trans-Danubian varieties have also resulted from the preservation of archaic features in the latter or from innovations that took place only there.
Romanian stands out from its sister Romance languages through the conditions of its historical evolution. It has developed in isolation from the other Romance languages, and in cultural and linguistic contact with various non-Romance populations. The history of writing in Romanian, and the earliest preserved texts, dating from the 16th century, also reflect this rather unique heritage. The main dialectal division is marked geographically by the Danube river. The variety developed north of the Danube forms the Daco-Romanian group, while the variety developed south of the Danube includes Aromanian and Megleno-Romanian. The most characteristic changes affecting consonants in the development of Romanian include several patterns of palatalization (with or without affrication, depending on the segments’ place and manner of articulation), the emergence of labial-coronal clusters as part of a more general preference for labials, and rhotacism, a major feature of nonstandard varieties. Major vocalic changes include patterns of diphthongization, vowel raising before nasals and in the context of trills, which led to the development of two phonemic central vowels, /ɨ/ and /ʌ/. Many of these patterns show variation among different varieties. In all varieties of Romanian, vowel alternations are involved in morpho-phonological alternations. The stress pattern of modern Romanian follows the stress pattern of Balkan Romance. The standard and nonstandard varieties differ with respect to their intonation patterns, particularly in the case of yes/no questions.