The speak-header property is used in aural media to specify whether table headers are spoken before each cell, or only before each cell if that cell uses a different header to the previous cell.
once − Headers will only be read once.
always − The contents of the header will be spoken as the preface to every related cell in the table.
object.style.speakHeader = "once";
All the elements that have table header information.
Here is the example −
<style type = "text/css"> <!-- table {speak-header: once;} th.urgent {speak-header: always;} --> </style>
For more detail please look into CSS Aural Media.