SwiftKey is one of the top choices for Android keyboards out there. It is my go-to and I strongly prefer it over Gboard for a variety of reasons. Regardless of where you stand, the best options offer a lot of language choices for either non-English speaking and/or multilingual users.
SwiftKey already has a large list of languages and dialects to choose from, and the latest beta version adds several more, plus some additional keyboard layouts.
The latest SwiftKey beta adds support for Cantonese and other new typing languages, plus more keyboard layouts [APK Download] was written by the awesome team at Android Police.