Anthony Navetta here with another blog post about my Quora account. As I have said extensively in this blog, I have done quite a bit of traveling over the years including internationally. A user on Quora recently asked whether or not people in Prague speak English and I added an answer based on my own experience:
In my experience, most locals in Prague speak some English but those born after the fall of communism are more likely to speak English since before the Velvet Revolution they learned Russian as a second language in school.
If you are sticking with the more touristy activities and locations, then the people in these locations will usually speak English. You will also find many signs in English and restaurants have English translations on the menu or English-language menus on request.
If you venture out of Old Towne Square then English speakers will be less common, and if you head to another Czech area like Cesky Krumlov, Sedlec, Kutna Hora, etc. then English speakers will also be less common there than in Prague.
Head over to Quora to see the answer and reply, or vote up my answer (the one written by Anthony Navetta.)