horrible noises

My system has, on more than one occasion, spontaneously begun making horrible noises. Don't have to be doing anything that generates audio. Orca wasn't even turned on and was not set to use cicero. The previous time this happened, I was able to trace it to speech dispatcher/cicero. pavucontrol was helpful. On the most recent occasion, I killed sd_cicero and the noise stopped.

The noise sounded like a stale ring buffer was suddenly being played continuously. The contents of which were extremely unpleasant.

sudo apt-get remove speech-dispatcher-cicero cicero

 dpkg -l | fgrep -i speech-dispatcher
ii speech-dispatcher 0.8.8-1ubuntu1 amd64 Common interface to speech synthesizers
ii speech-dispatcher-audio-plugins:amd64 0.8.8-1ubuntu1 amd64 Speech Dispatcher: Audio output plugins
ii speech-dispatcher-espeak-ng 0.8.8-1ubuntu1 amd64 Speech Dispatcher: Espeak-ng output module
ii speech-dispatcher-festival 0.8.8-1ubuntu1 amd64 Festival support for Speech Dispatcher
ii speech-dispatcher-flite 0.8.8-1ubuntu1 amd64 Speech Dispatcher: Flite output module
ii speech-dispatcher-pico 0.8.8-2 amd64 Speech Dispatcher: Pico output module

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: speech-dispatcher-cicero 0.8.8-1ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.11
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Wed Mar 4 00:26:38 2020
InstallationDate: Installed on 2019-05-02 (306 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: speech-dispatcher
UpgradeStatus: No upgrade log present (probably fresh install)