The television company uses a video translation filter so that all the ads appear to be in the native language of whichever country you are viewing in.
If you were going to invest millions of pounds in getting your adverts in direct view of the cameras, would you choose to use a Slavic language (which won't be understood by the vast majority of people outside the country which uses that particular language) or English (which is widely understood in all of the countries where the match is shown)?