An oratorical speech is a speech delivered in the style of an orator. The term itself is somewhat redundant, as the words "oratorical" and "orator" both relate to the practice of giving speeches.
According to Dictionary.com, the word orator means "a person who delivers an oration; a public speaker, especially one of great eloquence." Therefore, an oratorical speech would be one delivered especially eloquently. "Oration" also implies a speech that is generally given under special circumstances, such as a funeral, a graduation, a retirement party or a wedding. An oratorical speech would accordingly be a speech delivered for a special occasion.