I'm working on that. I'm using a program called "Speak". It's very old and actually runs on the Mac 512K with System 4.1. The problem is that the voice is so crude and computerized, that Siri has trouble with many words. Plus, I haven't figured out how to do long pauses, which is critical for sending off emails and texts, with subjects and the final "Yes" to send it off.
I have got it to give me the time.
I can get a text composed, but not sent out because of the pause needed before the "Yes" at the end.
Email is worse, becuase it requires a subject too.
Siri can sing "Daise" from 2001, but it thinks the Mac is saying "send" instead of "sing".
I'll get something going, and make a video.