This browser app adds Cantonese Yale or Sidney-Lau romanisation to any Chinese website or EPUB, but some work better than others. Tested on, but not affiliated to, JW. ORG and the Watchtower Online Library Chinese pages
Referenced Expressions is the creator of Cantonese Web & EPUB that is related to the Books & Reference category. The tool has been downloaded and set up by over 1K users and its latest release is dated Oct 16, 2020. Users rated this application 4.6 on Google Play.
It's free of charge to get the installer of Cantonese Web & EPUB, also, you can check out users' reviews on Droid Informer. The app works fine on Android 1.0 and above. The app is totally secure for downloading.