I'm really having a hard time finding answers to all the refined questions Allen asked. This site may help him answer the question about what is the capital of Montana. Then, here's a sample of Hoagy's "Stardust" - nice chance to train your ears a bit again, and find out about them changes yourself!
Here, then, is a website about professors (they should know, shouldn't they?) trying to work out why birds sing:
http://www.physorg.com/news3849.html.
This book may also be helpful, however only in respect to a very special and man-made species (but aren't all taxonomies man-made, in the end?):
That's how far I've come by now... if I have a few more glasses of guinness, I may or may not fine a few more answers.
Oh, I forgot one: the monkey/language question is highly debatable one - maybe Allen knows the answer but just doesn't want us to know?