I read that, you can change files under user directory to change the language of the spell check.. But that is so much work if you want to write a mail in dutch and two mails later you have to write an email in english.. Isn't there any solution when you have to write many mails in many different languages ??
Now you have to change the language in user file, then restart zimbra desktop,... every time when you write a new mail in different language..