Michael, I understand your desire for us to have our own language and I heartily agree that it is important. However, I don’t think I place the same level of urgency as you do with regard to this point. Most of the world speaks English, or a derivative thereof, so for Australia to do so is “the norm” (for want of a better term).
A lot of Asian and South American countries have languages which have roots in Spanish, Portuguese or even Dutch. I believe for the basis of the Australian language to be English is perfectly acceptable.
Those countries I spoke of, have all retained their own dialects in various parts of the countries. The Philippines, for example, has its main language, Tagalog, This is derived from Spanish. But there are over 700 different dialects in the Philippines which are not derived from other languages but are home grown. One that I managed to learn while there was Waray. The term Waray means “nothing”. The people of Samar call themselves the Waray, the nothing people.
I too have an interest in Linguistics, but mine is only a recent interest. My main interest lay in the origin of terms; sayings. I am looking forward to exploring this interest further, and perhaps writing about it in the future, when my understanding of the subject is more comprehensive.