This doesn't make any sense. Even you knew the C calling convention, but not C, where are you going to get documentation for system calls that doesn't use C code? The Linux, macOS, etc documentation uses C.
Reading the headers and prototypes in the man pages doesn't require "knowing" C. You just need to know the very simple subset of C's syntactical rules and the calling conventions. Anyway, reading C is far easier than writing C, most popular languages use the same syntax and operators.
