> It seems weird to me that someone would even want to settle in a foreign country without a good understanding of the language and cultural basics

These people typically call themselves "expatriates"

There's also supposed to be a distinction about intent to leave in a relatively short predetermined time period.

I consider myself an expat in New Zealand, because I'm on a ~2 year visa that cannot be extended, and I have no particular intent to try to transfer to a different visa.

If I'd been here the same amount of time, in the same job, but on a straight to residency visa I intended to convert to PR/Citizenship, I would be an immigrant.