To add a Google font to your site, go to Design Settings, and select the Fonts tab in the upper left. 

Next, select a Google font from the list, choose a font, and select the style. You'll see a preview of the font in the selected fonts to the right. 

To add the font you've selected, click on the SAVE button in the bottom right corner. 

Congratulations! You've added a new Google font to your site! 

Google fonts actually have a handy way to see if the language you'd like it supported by going to Google fonts and filtering the language. Like so: 

Voila! Now you can be sure the font you're adding supports the language you need it to.