You can absolutely learn the syntax of C in an afternoon, or a few days at worst, if you're not having to learn to all the other concepts interesting C programs

You can absolutely learn the syntax of C in an afternoon, or a few days at worst, if you're not having to learn to all the other concepts interesting C programs require. It is the same with any reasonably serious language. I mean you can learn Python syntax in an afternoon but it will be 6 months before you can use NumPy (and friends) without spending more time poring through the documentation than actual coding. Same with Java, C++, .NET, to be productive you must internalize a vast ecosystem and if you aren't doing it every (working) day then skill fade is very real.