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That said, most Dutch speak excellent English
That’s not true, not excellent English. Many speak enough to get by, except the elderly and the young, and some of them speak it well, fewer still excellently. Over four years, I’ve met probably a handful at most who could express their deepest thoughts and desires while pronouncing “th” correctly and their As not as Es.
Many banks won’t take you in if you don’t speak Dutch and it’s harder to find a job (this was in the news just recently, as it happens: nearly all international students are struggling in the job market because they generally don’t learn Dutch, despite there being so many vacancies). You can definitely get by with English, and I’ve heard of many people living here decades without learning Dutch too, but if you want to live well, that’s another thing altogether.
The good news is Dutch is easy if your mother tongue’s English or German but there is indeed a problem in the Randstad of it being hard to convince anyone to let you speak it with them, in part because they often overestimate how well they speak it. There’s a relatively famous quote from colonial Indonesia about how the Dutch colonisers would rather speak bad Indonesian than Dutch, which the Indonesians spoke fluently. I think it’s like a feedback effect with the reputation they have for knowing second languages.
Anyway, details details.
I imagine a lot has changed in that regard anyway, especially with the way mainstream politics has gone in the intervening years, but it does indeed sound like you lived in a bit of a bubble at the time too!
I’m British, and I know the British tendency is to understate rather than overstate, so I don’t know how you’ve landed there!
That’s why I expressly mentioned that it was because they don’t learn Dutch: so you don’t have to wonder if there were any confounding factors at play.
Dutch is easy (a relative term, admittedly) if your mother tongue’s English because they’re so closely related. Many basic words are either very similar or spelt the same but pronounced differently. Bit like what Spanish is to Portuguese. I think it’s quite obvious that native speakers don’t learn Dutch quickly, if at all, because they have no one to practise with, and perhaps the idea of switching languages being rude plays a part too. I’ve met a couple of people who think it’s not worth it to learn and none of them were from the Anglosphere.