Using AppleScript to launch specific tabs in System Preferences panes
The following works for me under macOS Sierra:

tell application "System Preferences"
    activate
    set current pane to pane id "com.apple.preference.keyboard"
    delay 1
    tell application "System Events"
        click radio button "Dictation" of tab group 1 of window "Keyboard" of application process "System Preferences"
    end tell
end tell