Hi NanaCA,
Thanks for posting in Apple Support Communities! Since you've already disabled VoiceOver but it continues to read out the typed letters, you may have spoken text enabled. Here's where to enable/disable this feature:
- "On your Mac, choose Apple menu > System Settings, then click Accessibility in the sidebar. (You may need to scroll down.)
- Click Spoken Content on the right.
- Turn on “Speak selection.”
- On your Mac, press the specified keyboard shortcut (the default key combination is Option-Esc).
If text is selected when you press the keyboard shortcut, the selected text is spoken. Otherwise, available text items in the current window are spoken; for example, if Mail is the current window, an email message is read.
If you set the option to automatically show the controller, it appears onscreen when your Mac starts speaking. Use the controller to change the speaking rate, move forward or backward one sentence in the text, pause and resume speaking, or stop speaking.
Note: If no text items are available, a beep sound plays.
To stop the speaking, press the keyboard shortcut again."
-Have your Mac speak text that’s on the screen
Disabling this setting will stop the spoken text from occurring. If it continues, restart your Mac and check for software updates. Outdated software can cause things to misbehave.
Cheers!