Hi Andrea

A list of Alerts and where they are triggered from is provided in the help docs

The language of the messages can be changed from within the activity through the messaging tabs for programs, certifications, Appraisals, seminar notifications 

In areas that don't allow the change to be made in the interface then you can change the language used in the messages through language customisation 

You need to search for the string and then type in the local customisation including the placeholder fields.

regards