This is a real pain point for me as a programmer in Prague. I want all programming language questions to return English results, because the Czech language has no stack-exchange ;), but I want all commercial queries to give Czech results, because I cannot even buy something in the US, even if I wanted to, they just won't ship here. This doesn't end up working very well unfortunately, and I don't know how to get the behavior that I want.

I am in Czechia as well and I never had this problem. Searching in English gives me relevant results (about the same as if I was in the USA) and searching in Czech gives me Czech results. Shopping works OK even with English searches - I'd get English speaking Czech shops or German/UK Ebay and Amazon.

I have all computer/browser locales set to US English, Google uses that but I remain on the .cz site. Works flawlessly.

I use one browser with a geographically based proxy and another one straight trough. Also, commercial VPNs are cheap and pretty reliable these days (the vendor I use has pops in majority of countries). Just a silly game to play with the content providers who are isolating users into specific market regions.

So now I need a VPN to buy cat food online ;) !

That sucks. One workaround you could use would be to have one browser profile for American searches and one for Czech searches, and flip between the two, even though it's a solution to make things suck just a little bit less.