What two things shaped southeast asia into a region of many different languages and religions?

The two major facts that shaped South East Asia as a region of many different languages and religions are consisting of 11 countries in it and major trade has been done in these 11 countries.

The South East Asia is formed by a major group of 11 huge countries which are generally divided into mainland zone and the Island zone that reach from India to China. Some of these mainlands are an extension of Asian continent. The Islam is the major religion in South East Asia with following of 240 millions of adherents and followed by Christianity, Buddhism and Hinduism.

The region has a very complex language pattern. Some major languages of the South East Asia are Chinese spoken by most of the people because China has the largest population of 1.4 billion followed by Hindi with a total of 550 millions of speakers, next is English which has 300 millions of speakers and then comes the Russian language which is majorly used in Russia.

the boundarys like convergent divergent and transform it causes subduction