The aim of this project is to investigate to what extent colloquial Latin was influenced by the constant contact with Greek during the archaic and late period. The main focus lies on non-standard varieties of language, notably those that may provide us a glimpse into spoken Latin. To this purpose, two groups of sources from two different periods will be analyzed and compared. The first one, from the 3rd to the 1st century BC, includes ancient comedies (Plautus and Terence) and the fabulae Atellanae. Of special interest are the sections involving people of lower social classes, such as slaves or pimps, the language of which is characterized by Greek and colloquial elements. The second group embraces selected literary and non-literary texts from 3rd-7th century AD. Special attention will be given to technical treatises (veterinary, medicine, etc.) and Christian works (notably Bible translations), whose language constantly deviates from literary norms and is deeply influenced from Greek.