Our Australian language is a form of the English language.
The English language has a remarkable history in that it is made up of many languages. The language of the British Isles (England) was originally the language of the Picts, the Scots, and the Celts. The Romans invaded Britain in 55 BC and their language was mixed in with the language of the original inhabitants. The Romans occupied Britain for 400 years until the 5th century. When the Romans left, Britain was invaded by tribes of the Angles, Saxons and Jutes from the North Sea shores of Europe. Britain became known as “Angleland” from the Angles and eventually became England.
From these invasions, the mixing of the languages became known as Anglo-Saxon or Old English. This form of the language lasted until the French invaded in 1066 with William the Conqueror. The French tried to make their language the language of Britain, but the common people held onto their Anglo-Saxon language. Many words from the French language were adopted and adapted into the Anglo-Saxon language which then became known as Middle English.
The French, being great cooks, used their words for an animal when it was dressed for the table. When the animal was living it was called by its Anglo-Saxon name. Those words have carried over into our modern language where live animals are named by Anglo-Saxon words, cow, sheep, pig, goat, deer, and when dressed for the table are named by French words, beef, mutton, pork, chevon and venison.
During the 17th Century, through changes made to the long vowel sounds, Middle English became Modern English. Also, during the 15th century, the printing press was invented and word spellings became standardised. Prior to the printing press, many words were written in whatever form the writer chose.