The speaker of the United States House of Representatives, commonly known as the speaker of the House, is the presiding officer of the United States House of Representatives. The office was established in 1789 by Article I, Section 2 of the U.S. Constitution. The speaker is the political and parliamentary leader of the House and is simultaneously its presiding officer, de facto leader of the body's majority party, and the institution's administrative head. Speakers also perform various other administrative and procedural functions. Given these several roles and responsibilities, the speaker usually does not personally preside over debates—that duty is instead delegated to members of the House from the majority party—nor regularly participate in floor debates.

Source: Wikipedia