A Latin motto in an English novel, or a line of German in a Polish one, reads better when the book says which language it's in. E-readers then read it aloud in that language's voice, screen readers pronounce it properly, and print hyphenates it by that language's rules instead of the book's.
Mark a passage in the editor: select the words, then choose Language and pick the language. A marked passage has a dotted underline in the editor. To take a mark off, select the words, choose Language, then Not another language. Passages marked in a Word document or an EPUB keep their language when you upload it.
Find the ones to mark: the Proofread tab lists the passages already marked, by language, and those that look like another language but aren't marked yet:
- words and phrases in italics whose words the book seldom uses outside italics, the way fiction usually sets foreign words. Emphasis and thoughts in italics are left out, since their words appear everywhere; so is a run of capitalised words, which is usually a title or a name.
- words in a writing system other than the book's, such as Cyrillic in an English book.
Each has its chapter, the words around it and a link that opens the editor there. The studio doesn't guess the language: you choose it when you mark the passage.