Annie Lennox’ cover:
And no, I didn’t want it that way. Unfortunately, for some reason, instead of using my selected language in Calendar, Google seems to use a badly implemented combination of location sniffing and browser/client accept-language header to specify the language of the feed.
Officially there is no way to set the language of the feed (parameter reference). The “locale” in the same page does not work for feeds, nor does “lan=en” as recommended here. However, non-feed related Google Calendar forum post pointed me to the right direction.
You have to append hl=en (or other google-supported two-letter language code) to your feed URL. So that /calendar/feeds/[email]/private-[key]/basic becomes /calendar/feeds/[email]/private-[key]/basic?hl=en – or, with the other parameters, /calendar/feeds/[email/private-[key]/basic?futureevents=true&max-results=100 to /calendar/feeds/[email/private-[key]/basic?futureevents=true&max-results=100&hl=en.