Highly depends on the country. Go to Sweden and you'll have a hard time even practicing Swedish, as soon as the natives discover you're also not a native, they'll switch to English immediately in most places of the country.

On the other hand, go to Spain outside the metropolitan areas and besides the youth, most people won't understand and can't speak English.

Then you have places like France, where even if many of them know English, they'll just refuse to speak English, unless it's an emergency, then English comes out of them with no problem. Then some French tourists also like to travel down to the North of Spain and try to talk French with us, for some reason. I cannot even count these occurrences on one hand anymore.

It really depends on the country and maybe more importantly, rural vs metropolitan areas.

Besides, humans are surprisingly good at communicating just with our hands, faces and pointing at stuff, you can definitively get by as a tourist in a country without sharing any spoken languages, and after a few days you'll both learn some of the basic words of their language, and "shortcuts" for pointing/hand-waving through what you want, making the whole thing a lot easier :)

It's no problem. At least in Spain, Portugal and Türkiye as an English speaker. I spent a few weeks solo traveling in those countries.

Sure you will encounter folks who don't speak English but you'll be surprised at how far body language can go along with understanding less than 10 words of their language. If it's important there's Google translate too.

But it's more fun without it. Years later I still have nice memories of chatting with a clerk at a small store to buy laundry detergent for washing clothes in a sink where neither of us knew each other's language. After 10 minutes of laughing and miming out the action of washing clothes we found a good powder that was safe for colored clothes, optimized for sink washing.

last time in Italy I "spoke" to lots of Italians very slowly with lots of gestures and a little bit of google translate, it was awesome and I learnt a lot! Nearly ordered 100x as much cheese as I meant to except the guy in the shop was not a computer so he understood what I really meant. Much better than in the Netherlands where they just switch to English as soon as they hear you try to say choodumorchen

I speak three European languages, and English worked almost always. Especially the younger folks in the cities. If it didn't work, I used a translation app.