Final answer:
The Vikings began arriving in Northern Europe and became traders and settlers. They were seafaring raiders who took the local languages when they settled.
Step-by-step explanation:
The people who began arriving in Northern Europe were the Vikings, who were Norsemen from Scandinavia. These Vikings became traders and settlers as they settled in the lands they had formerly raided. They were once seafaring raiders, known for their plundering voyages across Europe. As traders, they took the local languages and established trade routes like the one along the Dnieper River and settlements in Constantinople.