From Sonia reference page ( http://sonia.pitaru.com/ ) :

// Play a sample a twice its origianl speed.
// Notes: Make sure to include the specified audio file in your project's 'data' folder.

Sample mySample;

void setup() {
 size(100,100);
 Sonia.start(this);
 mySample = new Sample("sine.aiff");
 mySample.setSpeed(2);
 mySample.repeat();
}

public void stop(){
 Sonia.stop();
 super.stop();
}

I'm not sure what you mean by "tempo pitch".  By increasing the pitch by a factor of n, you also naturally change the tempo by a factor of n, and vice-versa.  (Half speed plays an octave lower, or half the frequency)

Maybe you mean timestretching?  i.e. changing the length, or speed of a sound but keep the apparent pitch the same?

Or do you want to perform a pitch shift, where the pitch changes but the apparent tempo remains the same?

To clarify, pitch and frequency basically mean the same thing.

If you have a sinewave at 440 hz (frequency), its an A note (pitch).  If you double the frequency to 880 hz, it is the A note 1 octave higher, playing at twice the original speed.

As far as pitch shifting and time stretching, sonia does not offer these functions.  They are actually very tricky to do well in realtime (especially timestretch).  

However, if you wanted to create the samples ahead of time, by manually writing an audio buffer, these effects are possible.  

Hope this helps.