Original: English had been the administrative language of the colonial government, and when Singapore gained self-government in 1959 and independence in 1965, the local government decided to keep English as the working language in order to maximize economic prosperity and because "with English, no race would have an advantage.
Simplified: English had been the administrative language of the colonial government, and when Singapore gained self-government in 1959 and independence in 1965, the local government decided to keep English as the working language.