To be honest I distrust Microsoft with swift key, but the it recognizes the change in language just smooth. I could switch languages in one sentence and it would understand what I am writing just fine, no Sill suggestions
Maybe the (most likely) AI-based thing requires some training though. I got my new iPhone a month or so ago.
With an iPhone, it's only one company, that controls every little thing, and we have no insight into Apple at all. They can basically do whatever the hell they want.