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Could anyone give examples about formal English and informal English? (words,phrases,etc)

I wanna speak english, I gonna work, kinda that are informal for example. I want to speak, I am going to work, Kind of that are formal.

formal english i think (correct me if am wrong)
are those phrases or sentences that stated in right grammar...
while informal are those phrases which you can state anything as long as you will be understand by others....

Examples: (colloquial english)
got to= gotta
want to= wanna
going to= gonna
C U/cya= see you
x x= kisses
ect....

part one

Basically, formal English is what you find in the English dictionary, academic writing, newspapers, business letters, and so forth. Informal English is mostly slang (those of you who don't know what slang is can look it up at www.google.com) and / or a greater or smaller percentage of our day-to-day spoken language).

I will give some examples here, but if you really want to learn informal English, listen to a lot of rap music, or hip hop in general (or "hippity hop" in the words of the actress Irma P. Hall in 'the Ladykillers', a film also starring Tom Hanks and Marlon Wayans) - my personal favourite rap singers are Kayne West, Mos Def, and Coolio. 50 cent uses a LOT of informal English, and I like some of his songs (and the film 'get rich or die trying', with 50 cent himself as main actor!), my only qualm with him being that some of his lyrics (from what I can understand) are sexist.

informal ......................................... formal
ain't .................................. isn't ("is not" is even more formal - only for school essays and the like)
gonna ................................. going to
wanna ................................ want to
wassup (what's up, or what's happening) ...... what's new / how are you?
rat ........................... a tattletale (or someone who denounces - 'tells on' somebody else)
scab ........................ people who go to a workplace to fill in for workers who are on strike
sucker ..................... credulous
pissed .................... drunk (Britain); angry (US)

part 2

everything seemed hunky-dory............ everything seemed fine (old slang but still used)
the fuzz (or the cops)........................ the police
crib ....................... house (rap)
little squirt ............. (offensive) a small child
kid ......................... child (common usage - comes from kid = baby goat)
hunk ...................... a man (used approvingly by women - e.g. 'what a hunk of a man')
broad .................... what an Italian gangster would use for 'woman' in a gangster film.
lovey-dovey ............. romantic (like two doves in love)
me and my homies .... (rap) my friends and I
to kick the bucket ..... to die
small fry (noun) / small-time (adjective) .... unimportant

Then there is also a vast range of 'substitute words' called Cockney rhyming slang. Basically, Cockney is the English spoken in one of London's poor neighborhoods, and it is very rich in slang, but a slang that has a structure of its own: a suit is called a whistle, because instead of saying 'suits', they would say 'whistles and flutes' (I don't know when or why that began, but it is fun, and it sounds cool!). Chairs: 'ladders and stairs' (thus a room 'with a table and a ladder' in it would actually be one with a table and a chair, ha ha).

It even spread to common American slang, for example in the expression 'to get down to brass tacks' (to get down to the facts - most Americans don't know it, but the expression came from the Cockney rhyming slang 'brass tacks' for 'facts'). Not to be confused with high brass, which is a high military rank, because of the medals, some of which are made of ... brass.
For some examples of Cockney rhyming slang, here is a good site:
http://www.cockneyrhymingslang.co.uk/cockney_rhyming_slang
You can find all sorts of slang dictionaries (both on the internet and as books). I will not post any links here because there is quite a lot of foul language in most of them...