Possible solutions:-

1. Verify the Voices
   Ensure that the voices are correctly installed and accessible by SAPI5. You can do this by running the following code to list all available voices:

import pyttsx3

engine = pyttsx3.init("sapi5")
voices = engine.getProperty("voices")

for voice in voices:
    print(f"Voice: {voice.name}")
    print(f" - ID: {voice.id}")
    print(f" - Languages: {voice.languages}")
    print(f" - Gender: {voice.gender}")
    print(f" - Age: {voice.age}\n")

2. Check Registry Changes
   If you made registry changes to unlock more voices, ensure that these changes are correct. Undo any changes if possible to revert to the original state. Here is a summary of what the registry changes might look like:

Open regedit.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SPEECH_OneCore\Voices\Tokens.
Ensure that the subkeys under Tokens correspond to actual voice files on your system.
3. Reinstall SAPI5 Voices and libraries
Reinstall or repair the SAPI5 voices.
4. Modify Your Code
There might be an issue with how the voices property is being set. Instead of engine.setProperty("voices", voices[0].id), it should be engine.setProperty("voice", voices[0].id).

import pyttsx3

# Initialize the TTS engine
engine = pyttsx3.init("sapi5")

# Set volume level
engine.setProperty("volume", 1.0)

# Get available voices
voices = engine.getProperty("voices")

# Print the first voice ID
print(voices[0].id)

# Set the voice to the first available voice
engine.setProperty("voice", voices[0].id)

# Speak the text
engine.say("hello world")
engine.runAndWait()

Hope this helps
Thanks

Yep. I"ve seen something similar here when you mess around with voices in the registry. Its really easily done (I was thinking of doing better exception handling here but its tricky). The key giveaway is this _ctypes.COMError: (-2147200966, None, (None, None, None, 0, None))

As well as editing HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SPEECH_OneCore\Voices\Tokens - also check
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\SPEECH_OneCore\Voices\Tokens

also
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SPEECH\Voices\Tokens
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\SPEECH\Voices\Tokens

Hello, I"ve encountered a similar issue.
engine.runAndWait() was constantly getting stuck. Nothing would be said, or of I tried to save to a file it would be just empty. After enabling debug I got the same _ctypes.COMError error as mentioned previously.
I decided to check the voices with the method provided by @Siddharth-Latthe-07 and it"s wierd:

Voice: Microsoft Zira Desktop - English (United States)
 - ID: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Speech\Voices\Tokens\TTS_MS_EN-US_ZIRA_11.0
 - Languages: []
 - Gender: None
 - Age: None

I don"t know if the registry is broken on my machine or I have to install SAPI5 separately.

Nope. A fix is coming...infact I"ve merged the pr for this today. Try using this repo instead of a fixed release number to see if it"s fixed. Once a few things settle I think we will push a new release.

pip install git+https://github.com/nateshmbhat/pyttsx3.git

At least I hope it is! Let me know.

Nb. If you come across and are using espeak. That"s coming too #363