The trick here is to know which skills you need and which ones cross over. There are lots of families of languages, and maybe that's a better way to evaluate. I

The trick here is to know which skills you need and which ones cross over. There are lots of families of languages, and maybe that's a better way to evaluate. If you need a C programmer, then you want to know they can manage memory. If you want a Haskell programmer, you want to know they can handle difficult functional abstractions. So there are certainly cases where you need to worry whether they have the transferrable skills, but it doesn't necessarily mean they have to know your exact language.