If you what Pathauto to transform caracters with accents into simple letters like:
- éèêë to become e
- àâï to become a
You must enable in Pathauto the option Transliterate prior to creating alias. But by default, you can't tick the checkbox.
You first need to rename a file. From within the Pathauto directory, rename i18n-ascii.example.txt to i18n-ascii.txt. Once renamed, you can enable the option from the Pathauto settings form.