Hello Fernando,

When you are in "preferences", choose dictionary settings.

Then you can select default dictionary, voice dictionary or temporary dictionary.

If you select Voice dictionary, you may add an entry for the voice you are just using.

If you want to add a Facebook entry to your Spanish voice, choose this voice in your Voice settings, go back to dictionary and voice dictionary, then add the pronounciation you wish to hear.

I hope this helps.

Best

Sylvie