I have 5 items in that bar on my Samsung Galaxy and I have no space for a label. As the screenshot shows the labels are there, just not visible until a certain breakpoint

I agree that the UX could be improved and there is plenty of evidence to support that. On the other hand the edit icon is super discoverable and used without the label so I think the challenge with the language icon is 1) there are not many multilingual sites and 2) the other icons there potentially cause the user to ignore them entirely.

Throw in the 200+ languages and longer labels in some of them and it becomes even more complicated...