ばか！バカ！　馬鹿ー月！

This thread is a collection of Japanese slangs & unofficial contractions. I'll start with a few and keep updating contributions, and arranging them in kana order. Please note that, colloquialism or contractions that have made it into the dictionary should NOT be here.

Slangs & Contractions

あ(a):
~ え/ぇ (~e) = ~い (~i); such as (ねぇ=>ない), (見てえ=>見たい), (めんどくせ=>めんどくさい), (しねぇ=>しない)

か(ka):

さ(sa):
知ったこっちゃない(shittakocchanai): an expression slang used to declare "doesn't really matter to me" / "I don't really care" to a piece of information or a matter.

た(ta):
とこ(toko) = ところ(tokoro)
だっせえ(dassee) = ださい(dasai) ((adj-i) primitive; unsophisticated; out of fashion)
だもん (damon) = だもの(damono)

な(na):
ねぇ (nee) = ない (nai)

は(ha):
ハンパじゃない(半端じゃない)(hanpajanai) = not too shabby(pretty good!)
ハンパない(hanpanai) = see ハンパじゃない(hanpajanai)
パネェ(panee) = see ハンパじゃない(hanpajanai)
ぶっちゃける(bucchakeru) = ぶちあける(buchiakeru)/ぶちまける(buchimakeru)

ま(ma):
もん(mon) = もの(mono)

や(ya):

わ(wa):


Internet Slangs & Contractions:
http://ofurotaimu.dreamwidth.org/6378.html

Native Dictionary for Colloquialism:
http://zokugo-dict.com/