Adding variety of accent and set it as options so that people can choose which accent they prefer to hear

While I was talking to ChatGPT I hear their voices and it was American accent. I wanted to talk with someone who has British accent for my study propose. When I asked them to shift accent from American to British, they said they are unable to do that. You should add more versatile accent such as British, Canadian, Australian even it can be asian ancient or Indian accent.