How do I access MacOS Sonoma Personal Voice from command line?

I've finished training MacOS 14.0 on my Personal Voice ("Myself"), and Live Speech correctly speaks phrases in my voice using the Live Speech interface. In **Terminal**, the command say -v '?' correctly lists my voice, but the command say -v Myself "Hello, World"; echo $? produces no audio output and indicates normal completion (echo $? => 0). I've tried rebooting. Is this a bug? Is there an additional step needed?