I'm not saying there are zero differences or that $other_language never has any new concepts to learn, but in functional languages variables are still variables

I'm not saying there are zero differences or that $other_language never has any new concepts to learn, but in functional languages variables are still variables, functions are still functions, conditionals are still conditionals, etc. Important aspects differ, but the basics are still quite similar as is a large chunk of the required reasoning and thinking.