In most of companies, Office is in English. But if you don’t feel comfortable with the functions name in English, you can easily switch the language of your Excel application to any other language. You just need to install an new Office Language pack.
In this page, you will download the most common Language pack for all your Office applications. Once you have install one of the Language pack, you will find in the same page a tutorial video to see how easy it is to change the language.