Mr. Chau is the protagonist of Payday. He is a 50 year old Vietnamese gambling addict living in Melbourne, Australia. 

He leads an elusive life, always disappearing for days, no explanation, no reason, leaving his wife alone to care for their son. He currently owes a lot of money to Horseface and Oxhead. 

For Chau, it is important for him to have an authentic Vietnamese accent. He is a pretty reserved  character so it's important to get that across in the acting. It would also be cool if he could have a raspy voice like he's been smoking for years.