We know that the use of AI has been on Yu Suzuki's mind, as it was his "keyword" for 2023 in Famitsu. Specifically, "light AI" or as
Switch noted in his translation, "light refers to not being overly heavy or complicated."
In this article, he seems to focus more on the visual/image generation aspects of AI, but anyone who is keeping an eye on developments knows that the use of AI is making rapid leaps and bounds in every direction. It seems logical that Yu Suzuki would be aware of its use for voice generation.
My thoughts turned to using it to mitigate the expense of voice actors for every minor NPC. I wouldn't expect it to be used for main characters, but... why not use it for pre-production to test out the timing of cinematics before bringing in the professional voice actors to do their lines in production?
To fabricate this recording would be a significant project of its own. The creator would have to know several details of the story that haven't been revealed in-game yet and are not widely known outside of the fanbase. Although, significantly, there is nothing within it that the most dedicated fans did not already know about. But there are some scenes, such as the little exchange with Shenhua, which would have to be imagined and scripted. There are certain sounds and intonations that aren't like anything I've heard in AI voice generation so far... but tools are being released almost daily so I certainly am not aware of everything that's out there.
Ultimately if we look at it as a fabrication, it is one that would have taken several days of planning and execution... not impossible by any means, but it's difficult to see the excitement of a fairly small community being enough of a motivation to dedicate the time to it. If someone wanted to get a rise out of people online, there are definitely topics with much bigger audiences to pursue. Maybe someone in this community who is super bored and isn't already channeling their energies into a more productive project..?
On the other hand, if it was really secretly recorded and leaked, who would risk such a thing? YsNet is a small developer and I can't imagine anyone there risking their job to do such a thing.
I also don't believe a professional partner being shown this as part of a presentation would jeopardize their relationship by leaking the audio.
How about a layperson who just happened to be part of a focus group of some sort? Well, how likely is it that they would already be aware of Shenmue and know of the Dojo? Not impossible, but not likely. (Anecdotally, I was once part of a survey and was shown trailers for unannounced movies, and I had never heard of any of them. I also had no impulse to do subsequent research to see if there was a fanbase out there hungry for information on any of them.) Furthermore, would Yu Suzuki himself really be directly involved in presenting a video for market research?
Lastly, there is the possibility that some have mentioned that this is legit, and it was "leaked" by YsNet themselves as a little get-ya-hyped to this specific community before they could officially announce anything. I mean... they've never done anything of the sort before, is all I can say about that.