If you have a static type system and it's sound, it'll reject some programs that would execute without type errors, whereas a dynamically typed language will al

If you have a static type system and it's sound, it'll reject some programs that would execute without type errors, whereas a dynamically typed language will allow such programs to execute: it's what I called "dynamic expressivity". That's why saying "more expressive" without qualifying whether one is considering "static" or "dynamic" is problematic.