template/html/jquery-tablesorter.js
function( c, $header, nextSort ) {
         if ( $header.length ) {
            var column = parseInt( $header.attr( 'data-column' ), 10 ),
             tmp = $header.hasClass( ts.css.sortAsc ) ?
              'sortAsc' :
              $header.hasClass( ts.css.sortDesc ) ? 'sortDesc' : 'sortNone',
             txt = $.trim( $header.text() ) + ': ' + ts.language[ tmp ];
            if ( $header.hasClass( 'sorter-false' ) || nextSort === false ) {
               txt += ts.language.sortDisabled;
            } else {
               nextSort = c.sortVars[ column ].order[ ( c.sortVars[ column ].count + 1 ) % ( c.sortReset ? 3 : 2 ) ];
               // if nextSort
               txt += ts.language[ nextSort === 0 ? 'nextAsc' : nextSort === 1 ? 'nextDesc' : 'nextNone' ];
            }
            $header.attr( 'aria-label', txt );
         }
      }
function( c, $header, nextSort ) {
         if ( $header.length ) {
            var column = parseInt( $header.attr( 'data-column' ), 10 ),
             tmp = $header.hasClass( ts.css.sortAsc ) ?
              'sortAsc' :
              $header.hasClass( ts.css.sortDesc ) ? 'sortDesc' : 'sortNone',
             txt = $.trim( $header.text() ) + ': ' + ts.language[ tmp ];
            if ( $header.hasClass( 'sorter-false' ) || nextSort === false ) {
               txt += ts.language.sortDisabled;
            } else {
               nextSort = c.sortVars[ column ].order[ ( c.sortVars[ column ].count + 1 ) % ( c.sortReset ? 3 : 2 ) ];
               // if nextSort
               txt += ts.language[ nextSort === 0 ? 'nextAsc' : nextSort === 1 ? 'nextDesc' : 'nextNone' ];
            }
            $header.attr( 'aria-label', txt );
         }
      }
nextSort (optional), lets you disable next sort text