~くなりました with ない


For example, if I want to say "(this food has) become not tasty", would the
correct way to say that be "おいしくなくなりました"? How would this be distinguished from
おいしく亡くなりました, "died tastily", however meaningless that may be? Is there some
more idiomatic way to say the former, and can I expect ない to behave perfectly
like a 形容詞?




> For example, if I want to say "(this food has) become not tasty", would the
> correct way to say that be "おいしくなくなりました"?

Yes, this would be a correct way of saying "(this food has) become not tasty".

> How would this be distinguished from おいしく亡くなりました, "died tastily", however
> meaningless that may be?

Context. Precisely because it's meaningless, and because it's a common grammar
point, and in writing due to the lack of kanji for 亡くなりました. The same way
おいしくなりました is not likely to be おいしく鳴りました, "rang tastily".

> Is there some more idiomatic way to say the former

おいしくなくなる is fine, but you could phrase it positively like まずくなる

> can I expect ない to behave perfectly like a 形容詞?

I think this ない is classified as 助動詞, while the ない in something like ケーキがない is
a 形容詞 (Sources: [goo
dictionary](http://dictionary.goo.ne.jp/leaf/jn2/162271/m0u/%E3%81%AA%E3%81%84/),
[goo
dictionary](http://dictionary.goo.ne.jp/leaf/jn2/162263/m0u/%E3%81%AA%E3%81%84/),
[oshiete!goo](http://oshiete.goo.ne.jp/qa/5686906.html)). But I believe you
can just think of it as an i-adjective in terms of conjugations.




> For example, if I want to say "(this food has) become not tasty", would the
> correct way to say that be "おいしくなくなりました"?

Yes, this would be a correct way of saying "(this food has) become not tasty".

> How would this be distinguished from おいしく亡くなりました, "died tastily", however
> meaningless that may be?

Context. Precisely because it's meaningless, and because it's a common grammar
point, and in writing due to the lack of kanji for 亡くなりました. The same way
おいしくなりました is not likely to be おいしく鳴りました, "rang tastily".

> Is there some more idiomatic way to say the former

おいしくなくなる is fine, but you could phrase it positively like まずくなる

> can I expect ない to behave perfectly like a 形容詞?

I think this ない is classified as 助動詞, while the ない in something like ケーキがない is
a 形容詞 (Sources: [goo
dictionary](http://dictionary.goo.ne.jp/leaf/jn2/162271/m0u/%E3%81%AA%E3%81%84/),
[goo
dictionary](http://dictionary.goo.ne.jp/leaf/jn2/162263/m0u/%E3%81%AA%E3%81%84/),
[oshiete!goo](http://oshiete.goo.ne.jp/qa/5686906.html)). But I believe you
can just think of it as an i-adjective in terms of conjugations.

