The Chinese Indonesians of Sungailiat mostly uses Hakka language since they're Hakka. Sometimes they mixed their language with Bangka Malay as well as a product of assimilation in culture.
The Chinese Indonesians in Sungailiat predominantly speak Hakka because they are Hakka people. Occasionally, they incorporate elements of Bangka Malay into their speech and also reflect the influence of cultural assimilation.