ServiceDesk 7.7.2 and above
Add a culture attribute on to another object i.e. Groups, so that you can use this in the email calculation shown in the Multilingual Content Pack documentation, instead of the User culture. For example, a French user may reassign incidents to a UK support group and the reminder or assignments would be delivered in French rather than English. So in this case you would want to use the culture from the Group in the calculation. The Multilingual Content pack can be found here: Multilingual Content Pack and the calculation is shown on page 14 of the pdf guide.
Step by Step:
In Object Designer, add a String attribute to the Group object with same length as the Culture attribute on the User object i.e. 50 and set the String SubData type to CultureName and save the changes.
In Window Manager, modify the window for Support Group and add the new Culture attribute on to the window and save.
You will then be able to set the Culture on each Support Group under Administration.
Then you can refer to the Support Group Culture attribute in your calculation.