Computer Configuration > Administrative Templates > Microsoft Edge
Both
HKLM\Software\Policies\Microsoft\Edge
Enables the Read Aloud feature within Microsoft Edge. Using this feature, users can listen to the content on the web page. This enables users to multi-task or improve their reading comprehension by hearing content at their own pace. If you enable this policy or don't configure it, the Read Aloud option shows up in the address bar, right click context menu, more menu, on the PDF toolbar, and within Immersive Reader. If you disable this policy, users can't access the Read Aloud feature from the address bar, right click context menu, more menu, on the PDF toolbar, and within Immersive Reader.