There are usually tons more options for voices on the Mac, such as Scottish and Indian voices for English. Does iOS 11 give you more voice options? Could someone go into the Accessibility settings in iOS 11 and go to VoiceOver -> Speech, then see if you have an option called "Add New Language" which was the name of the option in iOS 10. What options are you give for English? In iOS 11 they give you Australia, UK, Ireland, South Africa and US.