It's sad, but also fascinating, to see the pattern of deterioration in dementia. In this case there is a social as well as a linguistic issue. Many people maintain an politeness patterns well into dementia. They continue to greet people appropriately, thank them, and go through all the movements of chatting, even when they don't recognise their close relatives.
One factor here might be that her choice of language was closely linked to the basics of interpersonal action that choosing the right language was as automatic as saying 'hello' and 'goodbye'.
Someone somewhere must have studied it, but probably doctors rather than linguists.
Anthea Fraser Gupta
Hi, Talia,
I think Dr. Pyatt answered your question with the basics. It could be the case, however, that the dementia took away some parts of the brain but not others (what is known about the etiology of dementia, I think permits us to advance this as a possibility), specifically affecting in your grandmother's case the naming function before (or: and not) the 'language to use with X' function. We are constantly learning more about the brain, but as you can see, there are still many things we do not know.
Incidentally, there are aphasias (usually due to a cerebral stroke or other physical damage to (sometimes very isolated and specific) brain areas) which have similar symptoms to what your grandmother had. We have some ideas and clues as to what the causes are in some cases, but even so, careful researchers are loath to advance hard and fast 'reasons' even in the best-understood and clearest-cut cases. It has been amply shown, however, that even apparently unified functions in many cases are linked to various areas of the brain, even, for example, clearly lexical matters such as stress, intonation (eg in discourse markers) and specific language; but this is also the case in a number of very grammatical situations, such as inflectional irregularities.
Hope this helps.
Jim
James L. Fidelholtz
Graduate Program in Language Sciences
Instituto de Ciencias Sociales y Humanidades
Benem'erita Universidad Aut'onoma de Puebla, M'EXICO
I don't have a specific answer, but research has shown that memories are not stored in one place or in the same way. They can be split up into different types of information stored in different parts of the brain.
There are many studies of people with different types of head injuries who may lose one kind of memory but retain another. In some cases, the information may be available "subconsciously" even if a person cannot consciously recite the information.
It's appears that your grandmother lost access to who specific people are (or even just their name), but somehow retains information on which language to use with that person.
I can also tell you from personal experience that I can recognize people's faces and many contextual pieces of information, but may not be able to recall a specific name. An example may be "That villain in Star Wars ...
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