日本語と英語でかかれている本って英語でなんて言うの？

I want a book written in English and Japanese.
英語と日本語で書かれている本が欲しいです。

This is a book written in English and Japanese.
これは英語と日本語で書かれている本です。

This book is written both in English and Japanese.
この本は英語と日本語、両方で書かれています。

「日本語と英語の両方で書かれている本」ということですので、そのまま英語にして問題ないと思います。お役に立てれば幸いです。

英語と日本、両方で書かれている本が欲しいです。

... so that I can study English while enjoying the content.
そうすれば、英語を学びながら内容を楽しめるじゃない。

I would call a book that shows two languages a "book with translation". If it is specifically English and Japanese in the book, I would call it "a book that shows the English and Japanese translation." A simpler term could be: "a bilingual book." If I wanted to buy something like this at a book store, I would say: "I'm looking for a book that shows English with the Japanese translation."
I hope this helps! :)

For a book written in two languages, we refer to it as a bilingual book. Bilingual derives from BI- which means two, and -LINGUAL which means language. Literally, two languages.

Since bilingual books can be written in any two languages that you intend to reach customers that know both languages, it is necessary to specify the two languages which you want the book is written in. In your case, Japanese and English.

We can refer to a book with its text in 2 languages, as a Parallel text or dual language/Bilingual version...

This" parallel approach" can be very useful to help the reader grasp the subtleties between the two languages and even show up the distinct cultural references employed within the translations.

When a book is publish in one volume but in two languages we refer to it in one of 3 ways:
1. A bilingual book
2. A dual language book
3. A side by side publication
You have to state the languages you require. Often you can find easily books known as 'first readers' in dual languages for beginners. Higher level books are becoming more common.
If you want one you can ask to buy or purchase it. 'Buy' and 'purchase' are interchangeable in this context.

If you go to an international book shop looking for books you can buy that are in both English and Japanese, you can ask the owner: Can you provide me with a book that's in in both Japanese and English? Be prepared to give him a subject matter. Or, perhaps, he can take you to a bilingual section of the store where you can look at many such books and choose one. ))

A bilingual book.
I would like a book that is written in both English and Japanese.
I would like a bilingual book; written in English and Japanese.

When you want to ask for, or just know what a type of book is called, you have these three sentences/ name. The first one being the name of the book itself, and the other two are sentences you can use.

I hope this helps.
Have a great day.
Will