I have found that the Gujarati Microsoft Office Language Pack is available here:
(It was relatively difficult for me to identify it as I never learned to recognize the spelling of the word "Gujarātī" in Gujarati: ગુજરાતી. So, I had to find this spelling in Wikipedia and vaguely remember it while looking through the list box on this page; please appreciate my efforts :-))
You need to use "Select a language" list box to locate the language (as I did) and then use "Download" button to download it. It may or may not resolve your problem, because I know that not all language packs contain localizations of each and every Office component. If you cannot find MODI localization in this language pack, you can only appeal to Microsoft to find resources for covering this issue :-).