The excerpt provided in the question is from the English Bill of Rights. The text from that excerpt that states that those elected to office can speak freely while conducting government business is the following:
";That the freedom of speech and debates or proceedings in Parliament ought not to be impeached or questioned in any court or place out of Parliament;"
This part of the Bill of Rights makes reference to the freedom of speech of those who are members of Parliament. The Bill of rights is stating that all members of Parliament are free to profess their own opinions and believes when working, and that they can not be impeached by their opinions in any court or place outside of Parliament either.
The English Bill of rights is an act that the Parliament of England pass on December 16th, 1689, to create the separation of powers within the government, to limit the power of the King/Queen and to reaffirm the importance of freedom of speech.