The thing is, some of them aren't familiar with the programming language we're currently using, and I've been wondering whether they should be required to use it nonetheless in the home assignments, or use their language of choice.
What do you think? Is it too steep of a learning curve for a home assignment or is it legit? What did you do?
Home assignments should never be hours long - you can find a myriad of threads here on HN saying that's bullshit and I believe they're right. But IMO the best candidates are the ones that can teach themselves and know where to look when they have trouble, and in the post COVID world a remote interview is all you have.
So let's say you asked them to print out the first 50 Fibonacci numbers, nicely formatted. Could they figure out what you're asking, learn the 4-5 basic elements of your language (declare some variables, set up a loop, add two numbers, and print it out) and send it back with less than an hour's work? I'd say that's reasonable. If they sail through that first gate than you can always ramp up with a second assignment that goes deeper.
But I'd provide a language reference right from the start to save time. Don't make this an internet scavenger hunt for no reason.