here's one definition of peng
Adj. 1. The best, great, excellent,
often heard with reference to drugs.
E.g."This weed is peng!"
2. Of a person, very attractive, desirable.
one non-authoritative version of where it came from:
Basically, it means they think you're
good-looking/attractive - usually
referring to a girl. It can also mean
stoned/high on weed/cannabis. (It
originates in Nottingham.)
Here's the Urban Dictionary reference:
a word used in areas such as
nottingham to descibe something as
good. Can also be used to describe
someone as good-looking. see also bum
. oh my god, that jacket is proper
peng!
or
Yeh, i'd do him, he's well
peng.
Looking in COCA, how come is very common in American English. It's used to mean why, in questions, and occasionally in statements:
How come the reporters aren't asking that?
And that's how come this song "This Land Is Your Land" became known throughout America.
If we break down the places it appears, a pattern emerges: how come is almost never used where formal writing is demanded, as in academic writing, but is frequently used where informality is okay, as in fiction dialogue and speech:
TOTAL SPOKEN FICTION MAGAZINE NEWSPAPER ACADEMIC
HOW COME 2689 882 1318 283 164 42
In American English, at least, how come? is informal, but probably not considered slang.
Best Answer
The "jive style of slang" is a dialect of English, most commonly known as African-American Vernacular English. Americans might have heard in the 90s about Ebonics, which is the same thing. I don't think it is really appropriate to call it jive anymore. You can see from the Wikipedia page that it has many names, partly because it is a sensitive topic for many, and some names have become stigmatized.
Its precise origins are not entirely clear. Some speculate that it was English that was heavily influenced by West African languages, some believe that influence was minimal. In either case, it shares many features of Southern American English.