How did people settle in south and Southeast Asia?

During the colonial period, colonial powers had a significant effect on Southeast Asia. The physiography of Southeast Asia has been formed to a large extent by the convergence of three of the Earth's major crustal units: the Eurasian, Indian-Australian, and Pacific plates.

Explanation:

Besides the Europeans, Japanese and the Americans used to colonize Southeast Asian countries as well. Southeast Asians were under the European powers because Asian empires and kingdom declined while the Europeans became stronger.