Voice control custom command with variable?

I'd like to be able to declaim *"Keyword foo"* and have voice control, on hearing this, type :foo for me. Many of the built-in commands take 'parameters' (i.e., some following speech), so if it were possible to make a user defined command as such it would look like keyword , i.e., a 'variable' goes into the command (that variable being "phrase"). Is there a way to make a user-defined command which takes a variable as input, as many of the built-in commands do? That would be super useful. *I'm looking into whether it would be feasible to write code in an IDE (in my case, Clojure & Intellij) using only voice control (and perhaps an on screen control pad for help where needed e.g. that provided by the wacom cintiq), thus, keyboard free! - it would be amazing if this were possible.* I haven't yet explored what can be done with "run workflow". (I don't see any indication as yet that those can take variables, though). I've found the location of the default workflows: /System/Library/PrivateFrameworks/SpeechObjects.framework/Versions/A/Frameworks/DictationServices.framework/Versions/A/Resources/Workflows

mbp:Workflows m$ ll
total 0
drwxr-xr-x  12 root  wheel   384B 14 Dec  2019 ./
drwxr-xr-x  65 root  wheel   2.0K 12 Oct 16:30 ../
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 New Audio Recording.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 New Screen Recording.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 New Video Recording.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Apple Website.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Top Albums.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Top Family Movies.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Top Movies.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Top Music Videos.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Show Me Top Songs.workflow/
drwxr-xr-x   3 root  wheel    96B 14 Dec  2019 Take My Picture.workflow/

Update: realised I may be able to get half way to this by defining a command "To keyword", which could issue Alt+. But that's not just a 'keyboard shortcut', it's three presses. I haven't used automator yet but guess that might be able to do this.