The negative form of the 助動詞（じょどうし） (auxiliary verb) だ in Japanese frequently appears as じゃない
(an abbreviation of ではない). In 関西弁（かんさいべん） じゃない
is often replaced by ちゃう
itself is actually just an abbreviation of 違（ちが）う, a common うverb meaning ‘to differ’.
may be used directly after either nouns, or な-Adjectives
, to convey ‘is not (A)’.
Isn't that Emi's boyfriend?
Don't you think this dress is cute? I bought it yesterday.
may also appear in the past negative form. However, as it is a set expression (and not considered an actual conjugation of 違（ちが）う), it will not be conjugated like a regular う - Verb, but will become ちゃうかった.
Taro, wasn't your father from the Kansai region?
The teacher tricked us. The test is not easy at all.
Fun-fact - じゃない may also be replaced with やない
being the 関西弁（かんさいべん） equivalent of だ, with the い-Adjective
ない attached to it. Like ちゃう
is used after nouns, or な-Adjectives
Hey, isn't that Mio chan?
Look look, this was 50% off, don't you think that's a good deal?
When conjugating in the past negative form, やない
follows the regular conjugation rules of ない, becoming やなかった
That person wasn't Sanma-san. It was just a middle aged guy.
I bought this because it looked useful, but it was not useful at all.