I have always tried to pronounce names correctly, and I have a decent ear. However, with some languages, I apparently can’t hear some distinctions; there have been times when I was certain I was mimicking the sounds correctly, but the person repeatedly corrected me. It’s not (necessarily) that I can’t make the sounds, it’s that I can’t hear the difference between what’s right and what I’m saying. Chinese is one of those; I can’t get the romanized X and Z right.