There are attributes on xsl:sort that control the sorting:

• order='ascending|descending'

  This controls which way the sort is returned and defaults to 'ascending'.

• case-order='upper-first|lower-first'

  Defines which case is first and the default is language dependent.

• lang='' controls the language of the sort (e.g. French).

• data-type='text|number' controls when the data is treated as text or a number.

  This can also be a QName to specify processor-specific sorting.

  The default is 'text'.