Factors contribute to English becoming the most spoken language in the world:
The political power and importance of the British Empire led the people of India and Pakistan, Asia and Africa, North America, and Australia to study and speak English
The Industrial Revolution of eighteen century made English the language of trade, business and new technological inventions
The dominance of the BBC in English. English was the language of World news in business, trade, science and culture
By 1750 when British industrialisation had kicked off, the importance of the English language was utterly empowered and magnified by the nascent empire - the United States of America.
The tremendous success of the USA as a political and economic superpower makes English a must-to-have skill if one wants to participate in this successWith the popularity of Hollywood, American SItcoms English dominates the World cultural scene
English is a proto-European language and the most malleable of languages which also increases its reach
Therefore to be successful and advanced people should read, speak and understand English.
Chinese (Mandarin) will not overtake English as the most-spoken language because:
China does not attract top talent due to the autocratic political system resulting to all new technological and scientific inventions and developments taking place in the West
The vast majority of Chinese often copy what was invented in the West (English-speaking countries)
China’s autocratic political system is not attractive to copy or follow for progressive people
The Chinese film industry is not particularly attractive to other nations resulting Chinese not dominating the cultural scene
Therefore despite a large Chinese population, it is not absolutely vital to study and speak Chinese to be advanced.