The majority of the lines shown appear to be quite natural.
The Elder Scrolls V Skyrim protagonist was provided with voice acting in the style of Ciri from The Witcher 3 by Modder FearTcb; all lines are voiced by a neural network.
So the pronunciation of some specific words might sound strange to those who were initially told this by artificial intelligence. However, with phrases composed of ordinary vocabulary, AI handled the situation fairly well.
The neuro-Ciri variations, as they are pronounced, sound quite natural. Sometimes artificiality slips through the pronunciation, but it's still superior to nothing.
The Dragonborn Voice Over mod is a framework that allows you to add voice acting to the Dragonborn. Ciri's voiceover may be downloaded here.
The Ciri Witcher DBVO Pack is required for normal use; all other files are optional, as they include voice acting to a wide variety of fan content.
Neuro-Ciri has only spoken English until now.
This is an interesting article.