Proto-RomanianMain article: Proto-Romanian language See also: Origin of the Romanians, Romania in the Early Middle Ages, and Vlachs
The Romanian linguist Ovid Densusianu coined the term "Thraco-Roman" in 1901 to describe the "oldest epoch of the creation of the Romanian language", when the Vulgar Latin spoken in the Balkans between the 4th and 6th centuries, having its own peculiarities, had evolved into what is known as Proto-Romanian. Estimates of the ratio of Romanian words directly inherited from Latin range between around 20% and 60%. The proportion of words of Latin origin is especially high in the semantic fields of sense perception (86.1%), quantity (82.3%), kinship (76.9%), and time (74.7%). More than 90% of the function words, 80% of the adverbs and 68% of the adjectives in the Romanian language were directly inherited from Latin.
While some Eastern Romance variants and dialects adopted a number of loanwords in the course of their deveopment, others remained more conservative. In this respect, the Wallachian subdialect of the Daco-Romanian variant is the most innovative among all Eastern Romance subdialects. Many linguists and historians – including Grigore Nandriş and Alexandru Madgearu – even propose that the preservation of inherited Latin worlds by the subdialects spoken in the territory of the one-time "Dacia Traiana" province which were replaced by loanwords in other regions proves that these territories served as centres of "linguistic expansion". Likewise, the Maramureș subdialect of Romanian has also preserved words of Latin origin which disappeared from most other variants. On the other hand, Arumanian, although it is now spoken in territories where its development could not start still uses a number of inherited Latin terms instead of the loanwords which were adopted by other Eastern Romance variants.
No Latin terms connected to an urbanized society have been preserved in the Romanian language. Inherited Romanian words for "road" also reveal that the life of the Romanians's ancestors became more rural after the collapse of Roman civilization. For instance, the Latin word for bridge (pons) developed into Romanian punte which refers to a tree trunk placed over a ditch or a ravine, while the Romanian word for road (cale) developed from Latin callis ("a narrow foot path, a track"). Grigore Nandriş emphasizes that Romanian "terms for «to move from one place to another» seem to be particlularly numerous". Likewise, Romanian verbs referring to "going" developed from Latin verbs with a different meaning.
Based on the study of inherited Latin words and loanwords in the Romanian language, Nandriş, Schramm, Vékony and other scholars conclude that the Romanians stemmed from a population who inhabited the mountainous zones of Southeastern Europe and were primarily engaged in animal husbandry. For instance, Schramm emphasizes that "the Romanians inherited the word for «to plow» from Latin, but borrowed both the names of the parts of the plough and the terminology of the intricacies of plowing techniques from Slavic" which suggests that their ancestors only preserved some very basic knowledge of cultivation of plants. In contrast with these views, other scholars – including the historian Victor Spinei – state that the great number of names of crops and agricultural techniques directly inherited from Latin indicates "a very long continuity of agricultural practices".