Error 2 Unexpected error - Please file a bug report at http://bugzilla.xamarin.com. Reason: System.UnauthorizedAccessException: Access to the path "C:\Users\Ant├│nio Serpa" is denied. XShareSpeechin.Droid
Moving this to Android as it looks like an msbuild bug. We will need a fuller log to understand which target is throwing that, though. As a workaround, can you move the solution out of your personal folder? That should absolutely fix it.
Which Xamarin.Android version are you using?
In all likelihood, this is Bug #14918, which is fixed in C8 (not yet released, no release date).
In the meantime, please try using an ASCII path.
*** This bug has been marked as a duplicate of bug 14918 ***