Siri not providing spoken responses on my iPad

Expanding on Raine's reply, go to Settings -> Apple Intelligence & Siri -> Siri Responses and set it to "Prefer Spoken Responses", if it's not set that way already.

Regards.

Have you gone to Siri settings? There is a setting that turns off spoken responses. If that does not work you should check to see if your iPad is on silent mode as that could cause Siri to not speak.