https://arstechnica.com/tech-policy/2019/08/apple-will-stop-storing-your-siri-voice-recordings-by-default/

Apple will stop storing voice recordings captured by Siri-enabled devices except in cases when users intentionally opt in to the practice. "[B]y default, we will no longer retain audio recordings of Siri interactions," Apple said in an announcement yesterday. "We will continue to use computer-generated transcripts to help Siri improve."

The change won't take effect right away. The default storage of Siri recordings will stop "with a future software release in fall 2019," Apple said in a support document.