Currently in the language selection menu language entries disappear after a certain amount of time (Tools - Language - For all text, paragraph, selection etc. - or right click on the status bar).
For example, after using three languages, after quitting LibreOffice only default language remains.
It would be better to show the last three used languages always (maybe more), and have them replace only if more languages are used.
Seems like a viable enhancement to me.
Adding needsUXEval to bring it back into the spotlight of attention or to close it.
Personally I don't know if this is a real matter for many users. On the other side if you change between a handful languages in one or more documents it would be great to have a better proposal in the lists so that users have to do as few clicks as possible to make LibreOffice to fit their needs.