Can Mass Effect 2 Czech version be changed to English?

It's possible you already have the English files but just need to change a variable in a config file.

Go to the data folder in the Mass Effect 2 installation folder. If you have a retail copy, it's Program Files* - Mass Effect - Data. If you have the Origin version, it's Program Files* - Origin Games - Mass Effect 2 - Data. (*Program Files (x86) if you have a 64-bit OS.)

Open the sku ini file with a text editor. I personally prefer Notepad ++, but regular Notepad works fine as well.

Then change the language options to INT so it looks like this:

[SKU]
SKU=
VOLanguage=INT
TextLanguage=INT

If the English files are on your PC, then the game should be in English now. If not, you may have to find another way to get these English files. (I'd say by registering the game on Origin and downloading the game while your Origin client is set to English.)

I was going to suggest simply un-/re-installing (being sure to have a back-up copy of your saves first.) 

But fredvdp's way would be much quicker (if it works.)

Let us know what happens.

Good Luck.!

Right. Thanks for the advice, but I'm not sure, whether the english files are present. As it is a localised version, even the installer had only 4 languages, none of them english. I'll probably have to download the englisg files first. I'll have a look around. Hope it'll work, cause I'd definitely like to use the appearance pack and play the shadow broker missions...

Thanks a lot.

That worked for me from French to English, thanks a bunch for the tip!! 

Thanks so much for this solution. I am Czech myself, played the ME2 about half a dozen times and seeing the text suddenly in Czech really bugged me, I mean the translation is not terrible, but I prefer the original.