「口が X になる」: Craving for food?


In this picture below (I snipped it from the digital copy I bought online,
兄の嫁と暮らしています) there is this phrase "もう口がアイスになっちゃった". An obvious reading is that
she's really craving for ice cream. However, this is really an interpretation
than translation. What is the syntax/grammatical explanation for this use? I
assume it's of the form "口が＿＿＿になる" which is not obvious to me that it should
be read this way.

[![From the digital copy I bought online,
兄の嫁と暮らしています](https://i.stack.imgur.com/9U70i.png)](https://i.stack.imgur.com/9U70i.png)




Your guess is spot-on.

> 「口{くち}が + [food item] + になる」

is an idiomatic expression that means a person is thinking about a particular
food item so intensively that _**in his/her imagination**_ , s/he feels as if
his/her mouth were actually stuffed with that food item.

For that reason (← unintentional occurance), the verb 「なる」 is very often used
in conjunction with 「しまう」 as in 「なってしまう」、「なっちゃう」、「なっちゃった」, etc. in real life.

(Right now, I am murmuring to myself 「口がうどんになっちゃった！」 after having answered a
question about udon broth.)

Look here for [some real-life example
sentences](https://search.yahoo.co.jp/search;_ylt=A2Ri8cE7mj5d0B0AcK6JBtF7?p=%E2%80%9D%E5%8F%A3%E3%81%8C%E7%84%BC%E8%82%89%E3%81%AB%E3%81%AA%E3%81%A3%E2%80%9D&fr=top_ga1_sa&ei=UTF-8&aq=-1&oq=%22%E5%8F%A3%E3%81%8C%E7%84%BC%E8%82%89%E3%81%AB%E3%81%AA%E3%81%A3%22&at=&aa=&ai=AxG.JT6LQ5C9IoO9Koi4RA&ts=15383)
with the food item being 焼肉{やきにく}, a popular Korean-style BBQ.




Your guess is spot-on.

> 「口{くち}が + [food item] + になる」

is an idiomatic expression that means a person is thinking about a particular
food item so intensively that _**in his/her imagination**_ , s/he feels as if
his/her mouth were actually stuffed with that food item.

For that reason (← unintentional occurance), the verb 「なる」 is very often used
in conjunction with 「しまう」 as in 「なってしまう」、「なっちゃう」、「なっちゃった」, etc. in real life.

(Right now, I am murmuring to myself 「口がうどんになっちゃった！」 after having answered a
question about udon broth.)

Look here for [some real-life example
sentences](https://search.yahoo.co.jp/search;_ylt=A2Ri8cE7mj5d0B0AcK6JBtF7?p=%E2%80%9D%E5%8F%A3%E3%81%8C%E7%84%BC%E8%82%89%E3%81%AB%E3%81%AA%E3%81%A3%E2%80%9D&fr=top_ga1_sa&ei=UTF-8&aq=-1&oq=%22%E5%8F%A3%E3%81%8C%E7%84%BC%E8%82%89%E3%81%AB%E3%81%AA%E3%81%A3%22&at=&aa=&ai=AxG.JT6LQ5C9IoO9Koi4RA&ts=15383)
with the food item being 焼肉{やきにく}, a popular Korean-style BBQ.

