Unfortunately, I only know the answers to three questions on top of my head. I can answer the fourth but I need to do some research because I need to confirm it. Some of these answers are ones that I got from
Living Lingo:
1.
- Standard English is considered by many as a variety that is limited to the wealthy and highly educated. It is usually associated with elite groups such as the wealthy and well educated (as stated before) and they work in positions of power and influence such as government or the judiciary.
- It is commonly regarded as normative - that is, people believe that there is "correctness" in language and tend to use Standard English as a benchmark to judge other varieties.
2.
Dialect refers to the structural content of a speakers' language. This means the words that they use, syntactic structures that they deploy and their certain ways of expressing tense, plurals and so on.
Accent refers to the sounds that distinguishes where a speaker originates. For example, their intonation, the way the vowels and consonants are placed in patterned ways, the speed of their talk, etc.
I'm not sure about the second part of the question, sorry. :(
3. Possibly because Australian English was described as monotonous, lazy and careless up to 30 years ago:
"I think the Australian accent is ugly and grating on the ear". (Gilbert Mant, Interlude Program, ABC, 16 July 1958, cited p.119)
EDIT: I think with question 5, you have to talk about the unique characteristics of Australian English because our use of language determines who we are, ie. Australians.