The function of the government is to meet the real needs of the people. Unless the government knows what the people really need, it will not be able to meet those needs. Freedom of speech ensures that government officials hear the message of such needs. 
Freedom of speech leads to the uproar of public voices and is easy to disrupt social order. A good social order is a prerequisite for the government to meet the needs of the people.
 for a healthy country, freedom of speech is essential.