They include sermons and readings delivered at a wide range of events from weddings to jihadi recruitment sessions.
The material was discovered on a dozen of 1,500 cassettes found in al-Qaeda's headquarters in Kandahar, Afghanistan, which was evacuated during the US-led invasion in 2001.
Encompassing recordings from the late 1960s until the year 2000, the collection includes hundreds of sermons by Islamic scholars, political speeches by al-Qaeda's top strategists and even footage of live battles - as well as recordings of the group's reclusive leader. ...
Prof Miller's analysis of the tapes shows Saudi-born Bin Laden to be a skilled poet who weaves mystical references as well as jihadist imagery into his verse, reciting 1,400-year-old poetry alongside more current mujahideen-era work.
"[The readings] were sometimes given to large audiences when he was recruiting for jihad in Afghanistan... and other times they were delivered at weddings, or to smaller audiences, possibly in private homes," Prof Miller, a linguistic anthropologist specialising in the Middle East, told the BBC. ...
Prof Miller said that if alive, Bin Laden would still be writing poetry, which is central to the oral traditions of his tribal culture.
"Poetry is part of the oral tradition in the Arab world, which Bin Laden uses to tap into the cultural orientation, the history and the ethics of Islam," he said.
The tapes are currently being cleaned and digitised at Yale University in the US and public access is expected to be granted in 2010.
Prof Miller's findings are published in the October issue of the journal, Language and Communication.