How the CIA can verify that the voice was his.

American intelligence analysts say they have authenticated Osama Bin Laden's latest audio recording, which aired on Al Jazeera on Thursday. How do analysts confirm the identities of voices on tape? In March 2003, Brendan Koerner explained the key is creating a "digital model" of the voice in question, "using archived snippets from past speeches." And in November 2002, Christine Kenneally wrote that "[h]uman analysts are very good at doing the kind of thing most people do subconsciously—telling if someone comes from a particular region by recognizing basic vowel and consonant qualities."