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I used fromtexttospeech.com/ to create the audio file. I entered the text and selected the Create Audio File button.
I right-clicked on the created file and downloaded it to my computer.
I uploaded it to Google Drive.
In Drive I right-clicked it and set the sharing to anyone with the link can view.
I copied the shared link.
I pasted that link in the Embed insert function.
ENGLISH
 text to speech.mp3
text to speech.mp3GERMAN
 german.mp3
german.mp3BRITISH-FAST-HARRY
 british-fast-harry.mp3
british-fast-harry.mp3