NOTE: 'alternative' is to be changed to adaptation'.
I suggest:
This element is used to identify any alternative versions or adaptations of the content of a resource that may be substituted or used to augment it for a user, including content that can augment or replace only part of the content.
Note: Typically such additional content will be in another access mode but it may be in another language, reduced or enhanced literary forms, etc. Adaptations should be identified separately and, where possible, described as individual resources, including where they are components of a composite resource.
Liddy