There is no real opposite to "capital letters," but there is a verb "capitalize" (aをAにする) If you are referring to both as the same time, it is better to say "uppercase and lowercase" than "capital and lower case." If you say that a word is "capitalized," it means ONLY the first letter is an uppercase letter. If you are teaching a child, you should teach them "uppercase," "lowercase," and the verb "capitalize."

Thank you for your comment. They are really helpful for me.

I don't read Japanese, but I think I can magically figure out your question. There is absolutely no difference between the "capital letters" and "uppercase" in terms of usage, as far as I'm aware. ABC. <- I might say that was written with capital letters or uppercase letters. It is pretty much random which one I decide to use. So does that answer your question?

大文字=capital letter exemples The sentence should be start with capital letter. 小文字=small littler examples my email address are all small letter

質問が長すぎて、途中で切れてしまいました。続きは、「主に使いますか。どちらが、子供に教えるのにいいですか？」Thank you for taking your time.