SHAHT AAAAAHP!

[Sandman XI]

:v: You know, like Ahnuld says in Kindergarten Cop? It's funny because he's yelling at children.

So, how would you make a power that makes someone mute?

[Dr Archeville]

Intimidate.

Or, Transform (person to person with disability [mute])

[Raveled]

Obscure (Auditory)

Isn't there an outright Silence power in UP?

[Fox]

Yes, but it's a personal power -

Silence (Concealment/auditory, Action/Free (active), Range/Personal, Duration/Sustained) 1 or 2 pp/rank

You move with complete silence and do not give off noise unless you wish to, so long as you sustain your Silence power. You cannot be heard at all at distances greater than 30 feet. For double cost (2 points) you are also inaudible to high- and low-frequency sound and "invisible" to sonar and similar sonic sensors.

Associated Effects:

Immunity (sound) Your Silence might grant you Immunity to certain sonic effects, such as sonic damage (5 points) or all sound- and hearing-based effects (10 points).

S'pose you could give it affects others and maybe range....

[angrydurf]

It would be Concealment 1 (auditory) with the attack extra and whatever range you want to put on it (of course more ranks would allow it to be harder to save against.

That would silence all normal sound they emit. Now if you just want them not to be able to speak there're other ways with either mind control or a grapple or snare effect with chokehold or something similar.