if(  SpokenTo()  ) {
       Speak();
    }

##</code><code>##

sub Speak {
    return unless SpokenTo();
    # ...
}

##</code><code>##

sub Speak {
    return   if ! SpokenTo();
    # ...
}

##</code><code>##

DontSpeak()  unless SpokenTo();
DontSpeak()  if ! SpokenTo();

##</code><code>##

    unless( SpokenTo() ) dont {
        Speak();
    }