http://www.uesp.net/wiki/Skyrim:Fortify_Shouts
Quoted from that page:
Enchanting description: Time between shouts is reduced 20%.
Fortify Shouts is an effect that reduces the cooldown time between shouts. The magnitude of this effect is alternatively expressed either in percentage or in points. An effect with a magnitude of 0.2 point actually causes a 20% reduction in time between shouts. A magnitude of 0.2 reduces the ShoutRecoveryMult
actor value from its base value of 1.0 to 0.8.
Note that a display bug causes the effect text in-game to appear inaccurate in some cases. Whenever an in-game display shows the 0.2 magnitude, it rounds the value, meaning that the text ends up saying that the effect is 0% instead of 20%.
Enchanting
The following items use this effect, but none of them can be disenchanted:
- Amulet of Talos
- Ogmund's Amulet of Talos
- Raerek's Inscribed Amulet of Talos
Blessings
The Blessing of Talos reduces the time between shouts by 20%.
Bugs
The dragon priest mask Morokei is supposed to also have this enchantment, but due to a glitch it is never applied.
PC Only: This bug is fixed by version 1.1 of the Unofficial Skyrim Patch.
So, if you're on PC (and using the Unofficial patch), you can equip the Amulet of Talos, get the Blessing of Talos, and equip the mask for a total of 60% shout cooldown reduction. Not bad, and no "cheating" or exploiting involved.