@simon agreed, and to do that accurately, repeatably, and in a way that is automatable (e.g. unit tests) still requires knowledge of the language.
That kind of testing and review focuses on known-knowns (“this does what I expected it to do”) but largely ignores known-unknowns (“this does things I didn’t expect it to”) and unknown-unknown (“this does things I didn’t expect and I can’t see”). Those require language and tooling knowledge AFAICT.