Bronze Age
The history of Finland between 1500 BC and 501 BC
The Bronze Age began some time after 1500 BCE. The coastal regions of Finland were a part of the Nordic Bronze Culture, whereas in the inland regions the influences came from the bronze-using cultures of Northern and Eastern Russia. The question of the time lines for the evolution and the spreading of the contemporary languages is controversial, and new theories challenging older postulations have been introduced continuously. According to the recently most widespread presumption, Finno-Ugric (or Uralic) languages were first spoken in Finland and the adjacent areas during the (typical) Comb Ceramic period, around 4000 BCE at the latest. During the 2nd millennium BCE these evolved – possibly under an Indo-European (most likely Baltic) influence – into proto-Sami (inland) and proto(-Baltic)-Finnic (coast). However, this theory has been increasingly contested among comparative linguists. It has been suggested instead that the Finno-Ugric languages arrived in Finland later, perhaps only during the Iron Age. The Finnish language is thought to have started to differentiate during the Iron Age starting from the 1st centuries AD onwards.
Cultural influences from all points of the compass are visible in the Finnish archeological finds from the very first settlements onwards. E.g. archaeological finds from Finnish Lapland suggest the presence of the Komsa culture. The Sujala finds equal in age with the earliest Komsa-artefacts from Norway but may suggest also a connection to the Swiderian culture. South-Western Finland belonged to the Nordic Bronze Age, which may be associated with Indo-European languages and according to Finnish Germanist Jorma Koivulehto speakers of Proto-Germanic language in particular. Artefacts found in Kalanti and the province of Satakunta, for long monolingually Finnish, and their place-names have made several scholars argue for an existence of a proto-Germanic speaking population component a little later, during the Early and Middle Iron Age. Old Norse-speaking population settled parts of Finland's coastal areas in the 12th to 13th centuries. Swedish language differentiated from the eastern Norse dialects by the 13th century. During the subsequent Swedish reign over Finland particularly the coastal areas witnessed waves of settlement from Sweden.
References: Wikipedia