It appears that Cortana is expanding her horizons from this morning even further, with the immediate availability for native Spanish, Italian, German and French speakers to try it out in their own languages. Microsoft has said that the new languages for Cortana are still in early-release 'alpha' form, and those that wish to try it out must be enrolled in the Windows Phone developer preview.
Microsoft had already hinted at adding Spanish to Cortana in November, but it appears the rollout, which was scheduled for November, took a little longer than expected.
If you reside in any of the supported (and set) regions, an update will enable Cortana in those parts of the world, and is expected to be available later today. It's important to note that - since these languages and markets are only being supported in alpha form - you should expect bugs along the way.
Source: MicrosoftInsider.es (Spanish) Thanks for the tip Izan!