In less than two months, the indie film Dear You has become an unlikely mass hit.

Shot in the Teochew language from the Chaoshan region of southern China’s Guangdong province, the movie follows a man uncovering his family’s past by tracing remittance letters sent home from Thailand. As he pieces together his grandfather’s life story, the movie also explores Chinese migration to the region and the diaspora’s struggle to preserve its heritage.

In one scene, an elderly schoolmaster risks arrest in 1950s Bangkok to secretly teach diaspora children their ancestral Chinese tongue.

The movie has pulled in huge audiences and over 1.6 billion yuan (US$236 million) in China since its release on April 30.

But it has also sparked a debate across Southeast Asia about China’s soft power and political influence with Chinese communities in other countries.

The response has varied throughout the region – from Chinese-majority Singapore, to Chinese-minority Malaysia to Thailand and the Philippines where Chinese communities are more integrated into wider society.