While we're at it, let's switch to haskell (delete the unnecessary people argument):
greetABunchOfPeople = mapM_ (putStrLn . sayHello)
Explanation:
mapM_ is a function that takes two arguments.
mapM_ lambda list
It calls lambda on each element on list.
In the greetABunchOfPeople definition, notice we only gave mapM_ 1 argument instead of 2. That means greetABunchOfPeople would have to take an extra argument for the call to execute.
What I love about the Haskell version is it says only exactly what needs to be said.
sayHello - get the hello message for something.
putStrLn - send something to stdout
mapM_ - Do these things in sequence, I don't care about the result.
Together they say take a list of people, get their greeting strings and print them to stdout in order. It's hard to say it more succinctly without making things confusingly implicit.