Keyboard lagging since iOS 16 predicting both languages

So I had a iPhone XR and it lagged like crazy when we updated from iOS 15. We then realize that the keyboard prediction text was auto correct in Vietnamese and English. Despite the language chosen at the time was English.

we have tried resetting our keyboard, and various attempts of the tips and tricks discussed by Apple here. we are now led to believe that this is an iOS 16 bug, and hope that this issue gets resolved in iOS 17.

I do type in Vietnamese from time to time, but there should be no reason why I should predict Vietnamese text when I’m in English. this has never been an issue until I upgraded to iOS 16 and it’s a shame because I upgraded from iPhone XR to iPhone 13 Pro Max, and when the predictive text tries to predict both languages, it lags the keyboard a lot.

and I know I am not the only one with this problem because other family members have suffered from the same issue. again, resetting the keyboard dictionary does not work and I find it really annoying to get rid of the Vietnamese language because I do need to type in Vietnamese from time to time. please fix this Apple