For Google, I often find myself smuggling a "hl=en" into the query parameters. This works on almost all Google services, and is quicker than finding out where the language switcher is hidden in the UI.
I've been complaining about this for a long time now.
I wrote a small greasemonkey script to add hl=en to all except a select few google locations. They are the most egregious. Unfortunately for us the industry has chosen to go with IP address determines language and it's getting more and more common.
I DO have accept language configured in my browser and I also DO understand that statistically many people's browsers are mis-configured. NO. I'm not leaving my browsers logged in to every site in the internet.
Not all of their pages support the ncr. For example maps.google.com/ncr 404's. And without the /ncr I get redirected to .co.jp where there is no visible option to change the language unless I sign in.
