The OS is Pop!OS 20.04, a close derivative of Ubuntu (but I was told to post the question here). I don't think my question is pop or ubuntu specific.

I have masked these two services, and rebooted. Yet, they still show as enabled.

tim@indigo:~$ systemctl list-unit-files | grep speech speech-dispatcher.service masked enabled
speech-dispatcherd.service masked enabled
tim@indigo:~$

But despite that, the service is running with systemd as its parent, although it is running under my user. That is, the parent process (pid 2376) is

/lib/systemd/systemd --user

Is there a user-specific way of masking services?

Because systemd is the parent, I assume that it is starting as a service. How can something by masked and enabled (after a reboot)?

I don't know what is starting it. I don't want to remove the package which installed the service since it has some dependencies I don't want to remove. I think systemctl should let me stop this, but so far I obviously haven't worked that out.

 ps -aef | grep speech
tim        16850    2376  0 Aug31 ?        00:00:00 /usr/lib/speech-dispatcher-modules/sd_dummy /etc/speech-dispatcher/modules/dummy.conf
tim        16853    2376  0 Aug31 ?        00:00:00 /usr/lib/speech-dispatcher-modules/sd_espeak-ng /etc/speech-dispatcher/modules/espeak-ng.conf
tim        16859    2376  0 Aug31 ?        00:00:00 /usr/lib/speech-dispatcher-modules/sd_generic /etc/speech-dispatcher/modules/mary-generic.conf
tim        16862    2376  0 Aug31 ?        00:00:00 /usr/bin/speech-dispatcher --spawn --communication-method unix_socket --socket-path /run/user/1000/speech-dispatcher/speechd.sock