Translation:I know three people who want to learn Czech.
Would it be possible to consider adding "I know of three people who want to learn Czech"? Even though that would be better translated as "Vím o třech lidech, kteří se chtějí naučit česky" I think the meanings are similar enough to be included. I guess when I "know people" I really know them closer than "to know of people" where I know they exist, but I don't really "know them" know them. But my native English speaking husband insists "know people" is the same as "know of people." What do you think?
I believe your native husband is just wrong. We all make mistakes and hold strange notions, even in our native languages. The claim that there is no difference between "knowing people" and "knowing of people" is rather bizarre.
But now I know of one person espousing that striking view, even if I probably do not know them.
Perhaps he is just being misquoted. Obviously there is a big difference between knowing someone, and knowing as little as one thing about them. But the relative clause suggests that their desire to learn Czech is what groups them, not how well he knows them, and with the relative clause in place, I think the argument that the English speaker is distinguishing between people he knows of, who want to learn Czech, and people whom he knows well, who want to learn Czech, (omitting those other people he knows of who want to learn Czech, because he doesn't really know them well) is pretty weak, even given your strong example.