I don't see an "accept language" choice, but I see under my "wrench" in Google chrome settings/languages that I have English (United States), Dutch, and English (in that order).

2012/10/28 Platonides <platonides@gmail.com>
On 28/10/12 18:17, Jane Darnell wrote:
> Thanks for the quick reply! My preferences on commons are in English, as
> are my preferences in Google chrome (my browser of choice).

(If you are still seeing the in Dutch...)
Are you sure your browser is asking for web pages to be in English? Note
that this preference (Accept language) is a different one than the
interface language of your browser.

> I checked the link again and just noticed the languages on the left.
> I guess I was expecting a non-wiki survey site.

It is not really a wiki, it is only skinned to look like the wiki. :)
Much better experience than a foreign interface, IMHO.