keyboard/language detection/preferences stopped working

I have an iPhone 13 Pro Max with iOS 15.1.1

It used to be that iMessages, WhatsaApp, Instagram and other apps in which you text would recognize what the last language used with a certain contact/person was and store/switch to that language so that you could type with the proper dictionary and autocorrect, but it seems this has stopped working some weeks ago and I cannot find a preference or a solution online.

I have not performed any updates or changes to my system.

How can I fix this so that it goes back to recognizing the correct language among the 3 I have installed?