speechd-el customization

[Peter Vágner]

Hello,

Speechd-el has a functionality where it allows us to add list of 
function names which we don't want to have command keys spoken as these 
are pressed for.
By default pressing C-f C-b and many others works as intended. However 
when pressing M-f M-b command-keys are spoken.
What is a proper method to add more functions to the
speechd-speak-ignore-command-keys
variable?

I've tried to append the following to my ~/.emacs however I must be 
doing something wrong as I am still getting command-keys announced when 
pressing M-f M-b.

(setq speechd-speak-ignore-command-keys (nconc 
speechd-speak-ignore-command-keys
  '("forward-word" "backward-word" "forward-sentence" 
"backward-sentence" )))

By doing
(message "%s" speechd-speak-ignore-command-keys) C-j
in the scratch buffer prints out all the functions even the ones I've 
attempted to add.

What might I be doing wrong please?

Greetings

Peter