I can give an example of this not being a magic bullet for learning a language.

I used to work in Gibraltar and live in Spain. With the job being in Gibraltar though all business tasks were carried out in English, and the majority of my colleagues were British. Also in this kind of scenario you tend to have your work colleges as the people you socialise with.

My now wife and I tried to learn Spanish, but it was before we’d ever really taken note of the comprehensible input concept, and anytime we tried to use Spanish when we were out and about we wouldn’t have a clue what was being said back to us. It was pretty disheartening and we both just quit and went back to our safe little English bubble.

If you are so immersed that even your job is in the language of the country, then it’s hard to see that not being a major benefit in terms of learning the language.

But for people who are - to name one example - working in an English language school, it’s probably important to warn people before they go that in a lot of scenarios it’s very easy to surround yourself with the English language without necessarily intending to. You have to make a conscious effort to take advantage of being in the country.