Can I add custom words to Dictation?

Here is a functional example of a custom command. You have a document in the Finder that has its extension hidden, and you do not want to Get Info, and click unhide. Instead, you speak “show extension,” and dictation instantly unhides the document extension.

Here is the AppleScript that I have placed in an Automator Workflow's Run AppleScript action. This workflow can be saved anywhere in your home directory, or subfolder, as long as you can find it later.

tell application "Finder"

activate

-- document icon must be selected, and extension must be hidden

if not selection is {} and extension hidden of (selection as text as alias) is true then

set thisFile to selection as text as alias

set thisName to name of thisFile

set theNameExt to name extension of thisFile

set theBaseName to text 1 thru ((offset of "." & theNameExt in thisName) - 1) of thisName

if extension hidden of thisFile is true then

set extension hidden of thisFile to false

end if

say "File Extension restored to " & theBaseName & " dot " & theNameExt

else

sayuser_mistake

return

end if

end tell

tell application "SpeechRecognitionServer" to if it is running then quit

return

In System Preferences : Accessibility : Dictation : Dictation Commands…

1. Click + to add a new command.
2. Configuration
   1. When I say: Show Extension
   2. While using: Finder
   3. Perform: Select Run Workflow : Other... <locate, and click on the above Workflow file>, then click Open.
   4. Ignore Save Workflow As…
   5. Click the check box next to your as yet unnamed command, and it will become the When I Say string.
   6. Click Done.
3. Launch Dictation. Select a File without its extension showing, and speak your command. If your audio is on, it will speak that the file extension has been restored to the filename.
4. You may need to visit System Preferences : Security & Privacy : Privacy : Accessibility to enable Automator, or Script Editor authorization.

As a workaround try adding these words as individual names in Contacts. Mac Dictation uses the first and last names it finds in your Contacts application to improve recognition. Contacts are normally sync'd with Dictation after 10 minutes of telling Dictation to stop listening. Unfortunately, words cannot be removed from the built-in dictionary.

FWIW, I don't know that there is a way to add words to Dictation unless adding words to spell check would somehow work. I also don't know that you can remove any words.

I'm not sure why people are suggesting ways to add Dictation commands.

Guess I should make a new rule not to post anything after 5 PM as I would be too tired to read the original post.

Apple does not permit Dictation keyword extensibility. Users are confined to new Dictation commands that involve applications, or custom workflows.

Create your own Dictation commands, such as "make this speakable" as shown here:

macOS Sierra: Enable, disable, and create dictation commands