All the males, and I believe the females, have the same voices when doing dragon shouts.
Not true. I did a little testing a week ago or so, here's how it is.
Males:
Nords, Bretons, Redguards, Imperials and Argonians all have the same voice actor
Altmer, Dunmer, and Bosmer have the same
Orc gets his own
Khajiit gets his own
Females:
Nord, Breton, Redguard, Imperials, Altmer, Dunmer, and Bosmer are the same (tragic)
Orc gets her own
Khajiit gets her own
Argonian gets her own.
I don't understand why male Argonians get a recycled voice while the females get their own.