訂正<ていせい>correction
1.どうして「みんなさん」と言えば間違ったんですか→どうして「みんなさん」と言うと間違いなんですか。
2.皆の漢字は二つ読む体があります 一つ: みな 二つ: みんな→「皆」の漢字の訓読<くんよ>みには二つの読み方があります 一: みな 二: みんな
3.みなさんは正しいですがみんなさんはただしではありません それはどうしてですか→「みなさん」は正しいですが、「みんなさん」はただしくありません。それはどうしてですか。
4.スペイン語か英語の説明のほうがいいですよね→スペイン語か英語で説明してください。
回答<かいとう>answer
When kanji(the Chinese character) entered from China, "みなmina" was applied as kunyomi(a Japanese reading/Japanese translation) of "皆" (onyomi/a phonetic reading is "カイ"). The kanji "皆様" was applied to Japanese "みなさま". Afterwards, shape "みなさん" appeared as colloquialism. However, only "さま" is admitted as for kunyomi of "様" (in kanji of using regularly). Therefore, when writing by using kanji, "様" is changed into "さん" and it is written, "皆さん". Moreover, shape "みんな" appeared to "みな" as colloquialism(mina→minna ). However, only "みな" is admitted as for kunyomi of "皆" (in kanji of using regularly). Therefore, it is not possible to write by using kanji. It is necessary to write "みんな" by using hiragana. "みんな" is used only by "みんな". It is a mistake to add "さん" to "みんな". Why is it wrong? The reason is because Japanese people don't say so. To say so, it is said, "みなさん". Japanese "みんなさん" does not exist. It is an error which is easy to make a mistake in a foreigner. Please take care. Once again, "みんな" is not admitted as kunyomi of "皆 (in kanji of using regularly). "皆" might come out when inputting "みんな" in kanji conversion software, "みんな" might come out when inputting "皆" oppositely. But both of them are services for convenience(it is formally a mistake).