Our design and the wording is built for simplicity and with an international audience in mind. We use a lot of icons which help with navigation and of course you can customize the email templates, review questions and write feedback in any language.
Also you can just create cycles for your team in Beijing in Mandarin, in Paris in French or Rio in Portuguese. Our system supports all international character sets, and many of our clients have offshore teams and it works fine with them.
If in doubt, we'd suggest you conduct a limited (free!) trial with a couple of people from an international office. Sign up for a trial, here.