has there ever been a speaker of the house from the minority party
In modern practice, the Speaker is chosen by the majority party from among its senior leaders either when a vacancy in the office arrives or when the majority party changes. Previous Speakers have been minority leaders (when the majority party changes, as they are already the House party leader, and as the minority leader are usually their party's nominee for Speaker), or majority leaders (upon departure of the current Speaker in the majority party), assuming that the party leadership hierarchy is followed. In the past, other candidates have included chairpersons of influential standing committees.
Speaker of the United States House of Representatives