Correct Grammar for "Not My (insert item)"

[DeeLan]

Hello everyone,
How would I modify the phrase 「私の自転車」to expresses that the bicycle is NOT mine?
My gut says that the correct answer is 「私の自転車じゃない」however I wasn't sure whether the「じゃない」would negate the entire phrase to give "Not My Bicycle", or if it would only negate 「自転車」effectively giving me "My not bicycle" (obviously that sounds pretty wrong).
Is my gut correct or am I way off the mark?
Thanks,
Dylan.

[thegooseking]

Dylanさん, こんにちは、

私の自転車 is a noun-phrase, not a sentence. Like in English, noun-phrases in Japanese can't be inflected, so we need to pair it with a copula to gain inflections (just like we need conjugations of the verb "to be" in English, although verbs in English don't have a negative, so we also need the adverb 'not'). So we can add the copula to get 私の自転車だ - "It is my bicycle", then negate the copula to get 私の自転車じゃない . If you dig into it, this sort of means "(The statement) 'it is my bicycle' isn't (true)" but it's easier to translate it as "It is not my bicycle".

Remember, だ is, more than anything, an assertion that the clause it completes is true, so conversely, じゃない means that the clause it completes is not true. You also have things like でしょう which is the copula equivalent of adding そう to the い-base of a verb, indicating that it's something that seems to be true (based on your own observations; use だそうです for something that seems to be true based on what you've heard).

I have my own question on a similar theme, though. What is the difference between じゃなく and じゃなくて? I think I know the grammatical difference (じゃなく is an adverb and じゃなくて is the て-form of じゃない) but I still don't understand when it would be preferable to use one or the other, since they both seem to mean "not X, but Y". Some examples from jisho.org:-
百円じゃなくて、王冠でした。- It wasn't a 100 yen coin, but a bottle cap.
君だけじゃなく僕も悪いんだ。- We are both to blame. ("Not just you, but I, too, am to blame.")

Is it perhaps that じゃなく cannot modify a copula, but can modify a verb or い-adjective? E.g.:-
私の自転車じゃなく兄の物に乗った。- I rode not my bicycle, but my brother's.
私の自転車じゃなくて、兄の物だ。- It is not my bicycle, but my brother's.
Or am I on completely the wrong track?

よろしくおねがいします、
小狼

[community.japanese]

小狼さん、
こんにちは。
いつも詳しい説明をどうもありがとうございます。

Dylan san,
こんにちは。
The Japanese language has some negative from for noun phrases.
じゃない
じゃないです
じゃありません
ではありません
Also we have a rule longer is politer.
Therefore, the first one is most informal and the last one is most formal.

Yuki 由紀
Team JapanesePod101.com