[lvlrsSTI]

cantonese was the second most spoken language in china

it is said that KMT that rule china then uses  cantonese

Not sure about that, but the founder of ROC Dr Sun Yat Sen was Cantonese and he hired all the Cantonese as his top men, so called “Cantonese Gang”, initially the capital of ROC was in Canton and later moved to Nanjing. After Dr Sun passed away, CKS took over and he hired all the people from his hometown near Ningbo and Zhejiang province.