YOU SAID:
What do you want for dinner?
INTO JAPANESE
夕食は何にしようか
BACK INTO ENGLISH
What is dinner?
INTO JAPANESE
夕食は何ですか。
BACK INTO ENGLISH
What is the dinner?
INTO JAPANESE
夕食は何ですか。
BACK INTO ENGLISH
What is the dinner?
That didn't even make that much sense in English.