Most are available in audio and/or video plus their transcripts. Those addresses given prior to 1900 have transcripts only.The site includes a list of major journals in communication, with links to their websites. As this is a commercial site, the ads can be annoying.
American Rhetoric contains over 5,000 public speeches, sermons, legal proceedings, lectures, etc. in such categories as speeches by President Obama, movie speeches, and the top 100 American political speeches of the 20th century.