Source: The Straits Times Page A19, 18 Mar 2009
Speech by: Minister Mentor Lee Kuan Yew

Mandarin has to be the common language of Chinese Singaporeans. If the Government had left language habits to evolve undirected, Chinese Singaporeans would be speaking an adulterated Hokkien-Teochew dialect.

To effectively promote Mandarin, we closed down all dialect programmes on radio and TV from 1979.