Both use the same root words and both change over time.
Yes, English slang is.
Formal English is THE standard English. This is in oppsoition to informal English which is spoken English and includes slang and colloquialisms.
"Gotten" is considered standard English in American English, while it is less common in British English where "got" is preferred. It is not considered slang in either dialect.
It's slang for vagina. Similar to "p***y" in english.
Kriky is a form of Australian slang, not English, but I can see how you can get mixed up, the accents are similar!! :)
Yes, "wid" is a word, but it is not standard English. It is a dialect or slang abbreviation for "with."
Yes, slang is a type of informal language that consists of words and phrases that are not considered standard in formal English. It is often specific to particular social groups or contexts and may change frequently.
"Briefen" is not a standard English word. It may be slang or a non-standard term in some contexts.
Och, the wee bairn's greeting. That's English, but nonstandard. In standard English it's: Oh, the little baby is crying. How do people say it in your town?
"Vike" is not a standard English word. It could possibly be a slang term or a typo.
Presumably 'correct, grammatical Spanish' as against slang; the equivalent to Standard English.
No, "famousy" is not a standard word in the English language. It may be slang or a made-up term.