Singaporeans can speak perfect English infront of foreigners. However, just like the South Africans, the Jamaicans, they would use a patois language called "singlish" when communicating with one another.

In fact, I used to work for a Taiwanese boss and her English was pathetically difficult to understand. In Asia, I felt the worst spoken English or the most difficult to comprehend accent of English would be Taiwanese and Indoensians. I get very impatient when I listen to them, especially Indoensians speaking English.