The period during which Proto-Albanian and Latin interacted was protracted, lasting from the 2nd century BC to the 5th century AD. Over this period, the lexical borrowings can be roughly divided into three layers, the second of which is the largest. The first and smallest occurred at the time of less significant interaction. The final period, probably preceding the Slavic or Germanic invasions, also has a notably smaller number of borrowings. Each layer is characterised by a different treatment of most vowels: the first layer follows the evolution of Early Proto-Albanian into Albanian; while later layers reflect vowel changes endemic to Late Latin (and presumably Proto-Romance). Other formative changes include the syncretism of several noun case endings, especially in the plural, as well as a large-scale palatalisation.
