Conditional pluralize without the number

Perhaps this helps:

Kind of strange, though. The Sting::Inflections simply do a
Inflection.pluralize(word), and that method seems to return the word
only (the method I'm talking about is the one in the link above).

You'll need to use to_sentence to make a custom helper, in

def friends_list_to_sentence(friends)
  if friends.to_a.count == 1
    friends + " is your friend."
    friends.to_sentence + " are your friends."

That's quick and dirty and I didn't test it.