99.9% of the language used in the scheduler widget is customizable. The only two words that can't be altered are the "Login" and "Register" buttons in the top left hand corner. Here is how you can change the language in your scheduler:
First go to Setup->Scheduler as shown here:
Once you click on the Scheduler option, you'll see a series of drop down panels at the bottom of the screen:
Expand any of these windows and you'll see where you can change the text. For instance, when you expand the Welcome panel, here is where you can change the displayed text to another language:
Expand the rest of the panels to see where you can change the text on all the pages on your scheduler.