Google rolled out an update for its ebook app yesterday which should make it easier to read and/or mark-up multi-lingual books.
Google Play Books v3.15 now supports making highlights with stylus.
In previous versions of the app, a stylus worked just like a finger. You could use it to swipe the page or press and hold on a word to trigger the selection mode where you could either drag and expand the highlighted text to include more words, or use the dictionary and other features.
With the new app, you can just drag your stylus across a block of text and highlight it. When you release, the relevant action menu will appear.
That menu now includes the option to translate the text you highlighted:
You can find the app in Google Play; there's also a copy on APKMirror.