What is the official language of the host city for the Commonwealth Heads of Government Meeting in 1979?
English
Title: Commonwealth Heads of Government Meeting 1979
Passage: The Commonwealth Heads of Government Meeting 1979 was the fifth Meeting of the Heads of Government of the Commonwealth of Nations.  39 countries attended the meeting.  It was held in Lusaka, Zambia, between 1 August 1979 and 7 August 1979, and was hosted by that country's President, Kenneth Kaunda.
Title: Lusaka
Passage: Lusaka is the capital and largest city of Zambia.  One of the fastest developing cities in southern Africa, Lusaka is in the southern part of the central plateau at an elevation of about 1279 m .  s of 2010 , the city's population was about 1.7 million, while the urban population is 2.4 million.  Lusaka is the centre of both commerce and government in Zambia and connects to the country's four main highways heading north, south, east and west.  English is the official language of the city, but Nyanja and Bemba are also common.
Title: Commonwealth Heads of Government Meeting 1971
Passage: The Commonwealth Heads of Government Meeting 1971 was the first Meeting of the Heads of Government of the Commonwealth of Nations (formerly named the British Commonwealth).  It was held in Singapore, between 14 January 1971 and 22 January 1971, and was hosted by that country's Prime Minister, Lee Kuan Yew.
Commonwealth Heads of Government Meeting 1979 Lusaka