Why does Siri keep asking "Who is speaking?" on my HomePod?

You have indicated that you performed a reset and set up Voice Recognition many times, so I assume these conditions also are true:

• HomePod updated to latest OS (18.5)
• Personal Request are turned on
• You have allowed Siri in iCloud on your iPhone at Settings > [name on top] > iCloud > Siri.
• Your iPhone is close by when making the Personal Request
• The Language/Region in your Home settings for the HomePod are the same as on your device.
• You are not using a VPN on your phone

Set up voice recognition and Personal Requests - Apple Support

It is entirely possible that you do have a hardware problem that would require service or purchasing a different device from another manufacturer if you wish. Just trying to rule out any other possibility as the only time I will hear that response is when a family member who is not a user on the HomePod attempts to call or perform any other action requiring my personal information.

It is not recognizing you, you might want to reset the HomePods to see if the issues persist. If they persist and your HomePods are on the latest software version, you might want to give this as feedback to apple so that they can look into it. Please do so using this form: Product Feedback - Apple

jonierose19 wrote:

I’ve updated them, restarted them, and refreshed the setting for voice recognition.

Are you sharing your Apple Account with anyone else?