Some existing languages will be used while a few conlangs will be required. The purpose of the languages is to create suitable toponyms.
Nahuatl The lingua franca of the Aztec Empire.
Quechua The lingua franca of the Inca Empire.
Greek The Roman Empire's lingua franca.
Coptic For Egypt.
Romance languages It would be interesting to work some romlangs based on old languages: Gallecian (Galician-Portuguese), Asturan (Astur-Leonese), Visigoth (southern Iberian Romance + Aragonese), Pyrenian (Occitano-Catalan), Gallican (Common Oïl), Sardinian, Arpinan (Arpitan + Rhaeto-Romance), Lacian (Latioumbric + Tuscan), Italian (southern Italy and Sicily; heavily influenced by Greek), Adriatian (Venetian + Istrian + Dalmatian), Lombardic (Galloitalic), Dacian and Vandalian.
Germanic languages At least a form of German used by scribes in the Roman Crown. Most probaly a conlang derived from Old High German.
Celtic New languages ―or variations of existing ones― descended from Middle Irish: Irish (spoken in most of Ireland), Scottish Gaelic (Highlands and parts of northwestern Ireland, later spoken in Faeroe, Shetland and SW Norway), and Common Brittonic: Old Welsh (Wales and a strip in Western England), Cumbric (north of England, northern Lancashire and Scottish Lowlands), Cornish (Cornwall, Devon, Somerset, Dorset and Bristol area) and Breton (Brittany and western Normandy).
Classic Nahuatl will be used as the basis. Its orthography is regulated as follows: