I do pretty well in Thailand with English....In places where it matters (doctors, pharmacies, etc) it was always excellent. And the young generation is even better.
It is not fantastic but good enough....I recall in Italy, next to the Vatican, so a tourist spot, they pretended to not speak 1 word English...not even understanding Yes and No.
(But Italian is somehow very easy to learn for me....in one week I could understand many things, while Thai seems very hard for me).