How do you talk about things in parts?

Question

I would like to say "It is written half in English and half in Japanese."

When writing this myself I came up with:

これは半分英語で半分日本語で書いていました。

but I think that

半分英語で半分日本語で

does not sound very natural?

Answer 1

I think that

半分英語で半分日本語で

is fine. I think you could also say:

半分英語、半分日本語で

Answer 2

Using 半分 like that is completely fine. You can use other fractions as well (but in that case, you cannot use it adverbially and have to insert the particle を or は after it like 三分の二を). But if you do not particularly need to emphasize the act of writing, simply 書きました is more natural than 書いていました.