first.rb

module First
  def hello; "FIRST"; end
end

Speak.send :include, First

second.rb

module Second
  def hello; "SECOND"; end
end

Speak.send :include, Second

speak.rb

class Speak
  def hello_world
    complicated_hello_world_with_message hello
  end

  ...
end

speak_test.rb

def test_one
  Speak.new.hello_world # want module Second here but another_speak_test already included module First
end