I think I should contact espeak-ng maintainers to make espeak-ng support locale of Chinese correctly. Make zh-CN equal to cmn(Mandarin), and zh-HK equal to yue(Cantonese).
I find that espeak-ng has already treat 'zh*' same to cmn. So espeak-ng should not be the problem.
When I run `orca -s` to launch the setting window of Orca, there is drop-down menu for me to change speech language. However, it seems does not work.
The problem may lies in `orca -s` not work as I expected. When I click "confirm" button to save, it seems does nothing. If I close the window and re-run `orca -s`, it shows that the setting is not saved. I will investigate more in Orca.
Cameron