TTS Where can the pitch be adjusted?

[nosz]

I can change the options: text, locale and rate. Where can the pitch be adjusted? Is for the change the pitch a different plugin needed?

TTS .speak({ text: 'hello, world!', locale: 'en-GB', rate: 0.75 }).then(function () { alert('success'); }, function (reason) { alert(reason); }); }, false);