Unfortunately, there seems to be no option to change the default language. The most recent news I found here:
- http://unleashedmind.chipin.com/wysiwyg-api

So, as stated, trying a second time, and/or logged in Paypal may help.

There are more downsides to ChipIn behind the screens, such as that transfer fees are not included in the totals (as written on the page), but I will add a maximum of 15 dollars to compensate them. We're now little over 10 dollar on transfer fees.