Made for roughly the price of a single scene in a Hollywood blockbuster and filmed entirely in a southern Chinese dialect, the drama Dear You does not have the hallmarks of a box office hit.

But the independent film has unexpectedly become a sensation in China, receiving stellar reviews and sparking a wave of tourism to the small corner of southern Guangdong province where it is largely set.

Produced on a shoestring budget of just 10 million yuan (US$1.5 million), Dear You has already grossed more than 200 million yuan in China since its release on May 3. It is projected to eventually take about 800 million yuan – a record for a dialect film in the country – and is set to be screened at the Cannes Film Festival on May 15.

The film appears to have struck a chord in China – where young people are increasingly captivated by regional culture – by exploring the history of Chaoshan, a cluster of coastal districts in eastern Guangdong known for its distinct cuisine, teahouses and rich diaspora heritage.

From the 1800s, generations of Chaoshan people – also known as Teochew – left their homes in this historically poor corner of China to seek their fortunes across Southeast Asia and beyond – in Penang, Singapore and the United States. Famous for their clan-based culture, they formed tight-knit communities wherever they settled.

Dear You spans Chaoshan and Thailand, following a grandson’s search for his family history by tracing letters sent home decades ago. As he pieces together his grandfather’s story, the film explores the wider history of the great “South Seas”, or Nanyang, migration of the 1800s, when millions of economic migrants fled southern China.