This property specifies the average frequency of the speaking voice. Different voice families have different average frequencies (a male voice is approx. 120Hz, a female voice is approx 210Hz.)
<strong style="pitch: x-high">content</strong>
inherit: Explicitly sets the value of this property to that of the parent.
x-low, low, medium, high, x-high: These do not map to absolute frequencies since they are dependent on voice family. The obvious scale between values should be maintained no matter the voice family.
[frequency]: Positive number indicating average voice pitch measured in Hertz or Kilohertz.