[pointfree]

Most languages that aim to be minimal bake in a minimal syntax, but without implicit parameter passing, composability is not going to be extensible.

[bunderbunder]

In a forth-like language, you can think of all functions as implicitly being unary: They take a stack, and return a stack.

I've never used any other kind of concatenative language, so I'm less able to speak to them, but I'm guessing some similar situation applies for those as well.