Hi CarlFan-MSFT ,
Setting skipUserOOBE or skipMachineOOBE to 'true' will completely skipping the OOBE screens.
Set value "DIsableVoice" under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\OOBE to 1 (DWORD) and Cortana will stop talking. - This disables only the Voice.
I found the below registry key which worked for me, thanks
[HKEY_LOCAL_MACHINE\Test\Policies\Microsoft\Windows\Windows Search]
"AllowCortana"=dword:00000000