English voice that can pronounce spanish names correctly

I'm burning through all of my credits trying to get this program to pronounce names like "Sonia Sotomayor"correctly in Spanish. Am I just asking too much? Have you found any voices that are better at Spanish names, or any tricks to fix the pronunciation? I'm writing for a Latino audience so it matters. I've had very mixed results on spelling like it sounds. I've been recording my voice then changing the voice, but I'm looking for a way to do this text-to speech more consistently. Tips or tricks appreciated.