Spell check language keeps changing

[Kev]

I have always had a problem with the spell checker. I posted 2 years ago but got no help and now I've noticed a bit more detail about it.
I use both English and Japanese, but English is chosen as the default language in Options.
Any document I create starts in English on the Review tab under "Spelling", but the moment I click on the document, it changes to Japanese. When I click on the "Spell check" arrow, and then "options", it shows English is still the default language. So, I go back to the review tab, click on "Spelling", change it back to English and start typing... but it has gone back to Japanese instantly.
It still types in English but the spelling checker has changed itself to Japanese and so English doesn't get checked at all.
My OS is English, and Japanese is added as a Windows language pack.

[Jossi]

Language is also a part of character style, and character style can be a part of paragraph style. Maybe your default character or paragraph style has Japanese as language. When you open the right sidebar, you can check each character and paragraph style in use in your document by selecting one and clicking "Edit...".

[Kev]

Thanks for that information. I see under "character" that the language is "default" (English UK) at the start of the document but then I scroll down it changes to "Japanese", on some letters and back to "Default" again later down. I also notice that it sometimes shows "English US". So I'm wondering how it gets changed in different parts of the document.
Anyway, being aware of this means that I can quickly correct it when it occurs. Thanks.

[martin-k]

It seems you have a text that uses Japanese, but you have not turned on extended support for Asian scripts (see Options dialog).

When you do that, the Character formatting dialog will change, offering to set different font for Western, Asian and Complex scripts. I think this will make clearer what is going on.

[Kev]

Thanks, I'll work with that and see how it goes.