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