What is language?
That has been much on my mind lately. Good question. I think the answer is out there. In scattered form.
Language is first and foremost a means of expressing oneself, of expressing concepts. True language is composed of syntax -- the way in which seperate words relate to one another and to the world at large -- and grammar -- the accepted order in which words flow and are used. It is a temporal concept. A comes before B before C. Language is a means of expressing abstract ideas that one has no direct physical knowledge of as well as concrete ideas. Language is something that we know, but we don't always know that we know. It's functioning is so basic to our lives that it has been internalized.
Protolanguage is a trickier thing. It has no structure. It is mediated by the limbic system rather than the neocortex. It expresses emotion. It is not even necessarily used in the same way by the same species. I'm probably dead wrong about this concept. You're the linguist. You've explained syntax. Now, it's time to explain protolanguage.
The interesting thing about language is how our brains deal with it. The brain sets up feedback loops in which certain sounds are emphasized and certain sounds are de-emphasized. Infants are born with an open temporal lobe. They are capable of learning any language, hearing any sound. It is through the learning process that certain connections are cut back and we limit our perceptions to those sounds which are useful and proper for our culture.
In fact, our brains sometimes shift the order of sounds about. In experiiments, a word was spoken with a syllable missing and replaced with static. le...latures. The people listening "inserted" gis to hear legislatures. Another experiment the word tress was repeated over and over again. People heard dress, florists, purse, joyce, and stress. So, it is a search for meaningful utterances within a key framework of sound range.
Another example given is "when A. F. Chamberlain visited the Kootenai and Mohawk Indians during the late 1800's, he noted that they even heard animal and bird sounds differently from him. For example, when listening to some owls hooting, he noted that to him it sounded like "tu-whit-tu-whit-tu-whit," whereas the Indians heard "Katskakitl." However once he became accustomed to their language and began to use it, he soon developed the ability to hear sounds differently... When listening to a whippoorwill, he noted... it was saying "kwa-kor-yeuh." From the Naked Neuron. That's just some crazy stuff. I had always assumed that language allowed thoughts to work differently, but this is insane. The brain is a strange, strange place.