Enunciation is the art or skill or ability to pronounce words clearly. Some minor celebrities have it, and some don't. If, as an author, you are paying substantial prices to have your works put into audio form, even if a bot is doing it, you need to make sure that your voice-talent is adequate.
Take a current TV advertisement for a luxury, plumbing-related solution to a bathroom renovation. Do you know what grey water is?
Now, grey -or gray- water is fine and environmentally responsible for watering your garden, but there is a limit to its uses. It is not glamorous. Basically, it is used bathwater.
If you are hiring visual talent to pitch your product, you might want her to be able to enunciate "great" as opposed to "grey" or "gray" because great is fantastic, and grey in the context of water is... gross.
Otherwise, change the script. "Grea..." could be "Fantastic" or "Amazing" or any number of more easily pronouced synonyms.
All the best,