Go to https://settings.webex.com and select Webex Calling.
From the Calling User Portal, click the profile drop-down in the upper, right corner.
Click Account Settings.
From the drop-down menus under Announcement Language and Email Language, select your preferred language.
Calling User Portal | Change the Language for Your Audio and Email Announcements
You can change the language for your audio announcements, voice prompts, IP phone display, and for your email communication.