Determining the Southeast Asian country most similar to South Asia requires considering various social, cultural, economic, and political factors.
One way to answer this complex question is by analyzing the data from the Country Similarity Index. The index attempts to quantify how similar countries are to each other relative to other countries, using a variety of statistics from five broad categories: demographics, culture, politics, infrastructure, and geography.
(South Asian countries are defined as India, Bangladesh, Bhutan, Sri Lanka, and Nepal. Pakistan could be considered as either Middle Eastern or South Asian, but is included as well)
The influence of South Asian culture has been present in Myanmar for centuries. In fact, Myanmar was part of British India during the colonial period. It remained part of British India until 1937 when it became a separate colony known as British Burma. The country gained independence from British rule in 1948.
Southeast Asia has big disparities in wealth and education from one another. Relatively developed countries like Thailand, Malaysia, Singapore, and Brunei are part of Southeast Asia. On the other end of the spectrum, Myanmar is one of the least developed. South Asian countries tend to be less educated and not as wealthy as Southeast Asian countries, so Myanmar is more similar. A high percentage of its people are farmers.
Myanmar, like most South Asian countries, uses scripts derived from the ancient Brahmi script. The Burmese script, used for writing the Burmese language, has similarities with scripts used in many South Asian languages. Furthermore, Myanmar, like Bhutan and Sri Lanka, is predominately Buddhist. It is a Dharmic religion that shares cultural roots with Hinduism. However, the country also has a significantly percentage of Muslims and Christians too.
Myanmar borders two South Asian countries: Bangladesh and India. It is also the only Southeast Asian country that just borders the Indian Ocean and not the Pacific. In addition, Myanmar experiences a monsoonal climate, characterized by distinct wet and dry seasons. This climate pattern is also prevalent in South Asia, contributing to similar agricultural practices and ecosystems.
The Most Similar South Asian Country to Myanmar
The Country Similarity Index suggests that Bhutan is the most similar South Asian country to Myanmar. Just like Bhutan, Myanmar borders both China and India. Most people in these countries speak Sino-Tibetan languages. They are also both mostly Buddhist, although Bhutanese follow the Vajrayana tradition.