Multilingualism Helps to Stave Off Dementia.

A cheering Science News report:

A strong ability in languages may help reduce the risk of developing dementia, says a new University of Waterloo study. The research, led by Suzanne Tyas, a public health professor at Waterloo, examined the health outcomes of 325 Roman Catholic nuns who were members of the Sisters of Notre Dame in the United States. The data was drawn from a larger, internationally recognized study examining the Sisters, known as the Nun Study. The researchers found that six per cent of the nuns who spoke four or more languages developed dementia, compared to 31 per cent of those who only spoke one. However, knowing two or three languages did not significantly reduce the risk in this study, which differs from some previous research.

“The Nun Study is unique: It is a natural experiment, with very different lives in childhood and adolescence before entering the convent, contrasted with very similar adult lives in the convent,” said Tyas. “This gives us the ability to look at early-life factors on health later in life without worrying about all the other factors, such as socioeconomic status and genetics, which usually vary from person to person during adulthood and can weaken other studies.” Tyas added, “Language is a complex ability of the human brain, and switching between different languages takes cognitive flexibility. So it makes sense that the extra mental exercise multilinguals would get from speaking four or more languages might help their brains be in better shape than monolinguals.” […]

“This study shows that while multilingualism may be important, we should also be looking further into other examples of linguistic ability,” said Tyas. “In addition, we need to know more about multilingualism and what aspects are important — such as the age when a language is first learned, how often each language is spoken, and how similar or different these languages are. This knowledge can guide strategies to promote multilingualism and other linguistic training to reduce the risk of developing dementia.”

An apple a day and a language a year, that’s the ticket. (Thanks, Pat!)

Comments

  1. J.W. Brewer says:

    Neither the article nor the abstract seem to say how many of the 325 total were quadrilingual, and knowing how large or small that number was seems rather important in assessing how meaningful the result is.

  2. Indeed, you’d suspect a very small/meaningless sample size. Furthermore being quadrilingual might correlate with other factors in their “very different lives in childhood and adolescence before entering the convent”, such as the life experiences that gave opportunity to speak 4 languages.

  3. David Eddyshaw says:

    @JWB:

    Exactly so. It’s impossible to tell how meaningful this is without a good deal more information. It looks fishy a priori, discovering your hoped-for publishable correlation in a presumably really rather small subset, after failing to find it in larger subsets where, if the effect is real at all, you’d surely have expected to see something. There are huge statistical pitfalls lying in wait for studies like this: it’s no use at all doing fancy statistical tests for significance if you’ve (for example) thumbed through all of your data and retrospectively discarded the bits that don’t support your hypothesis (which you need to make absolutely specific BEFORE you look at ANY data.) I would have once thought that a published paper in a peer-reviewed journal would be unlikely to fall into the more elementary errors; experience has taught me otherwise.

    Quite apart from possible statistical misinterpretations (perhaps there aren’t any!), it seems especially rash to presume that correlation implies causation in a case like this. The backgrounds of genuine polyglots are likely to differ systematically from monoglots (for example, more likely to be African than European, more likely to be clever in general than stupid [which is in itself known to correlate with reduced risk of dementia.])

    All this is a pity, because all of us would so like it to be true …

    [Edit: Ha! beaten to it by AntC. Jinx!]

  4. I was hoping for the best, but I somehow knew it would get shot down…

  5. David Eddyshaw says:

    Well, it might be true. I’m going to learn more languages just to be on the safe side.

  6. David Eddyshaw says:

    Also:

    “Oh, don’t worry about Grandma! We think she’s perfectly lucid, but unfortunately none of us youngsters can speak Kabardian.”

  7. At least the notion that bilingualism is injurious to anybody, though it used to be commonplace, has been pretty well shot down, at least among the well-informed.

  8. David Eddyshaw says:

    True.

  9. David Eddyshaw says:

    This snippet

    The researchers also examined 106 samples of the nuns’ written work and compared it to the broader findings. They found that written linguistic ability affected whether the individuals were at greater risk of developing dementia. For example, idea density — the number of ideas expressed succinctly in written work — helped reduce the risk even more than multilingualism.

    suggests serious confusion about correlation vs causation. A predictor of dementia is by no means the same thing as a cause of dementia. “Helped reduce the risk” shows that the reporter (at least) has no understanding at all of this. (Perhaps they need to learn more languages?)
    There is nothing either new or surprising about a finding that higher cognitive skills go with a lower risk of dementia.

    Nothing in the accessible material tells us what they actually counted as “speaking” languages. Are these people who’ve grown up speaking four languages (half my colleagues in Ghana?) Are they people who’ve learnt several languages as adults (girly swots?) Lumping these groups together is unlikely to yield meaningful results.

    Perhaps the inaccessible paper is in fact much more robust and well-designed than these frustrating glimpses suggest. Or perhaps not.

  10. David Eddyshaw says:

    (Did they count Latin?)

  11. David Eddyshaw says:

    Absolutely and totally off-topic: I see that the on-line Guardian currently displays the the headline

    Doctor who
    clashed with Rees-Mogg to
    run in Javid’s seat

    The Doctor’s most evil enemy yet! Whatever you say about the Daleks (and they have their faults), they’re admirably forthright about their true objectives.

  12. More from the abstract:
    This significant protective effect of speaking four or more languages weakened (OR = 0.53; 95% CI = 0.06, 4.91) in the presence of idea density in models adjusted for education and apolipoprotein E. Conclusion:Linguistic ability broadly was a significant predictor of dementia, although it was written linguistic ability (specifically idea density) rather than multilingualism that was the strongest predictor.

    Learn written language! “Idea density” means something like “uses lots of adjectives and adverbs”

  13. David Eddyshaw says:

    Don’t omit needless words! Curse you, Strunk and White! you’ve doomed us all!

  14. David Marjanović says:

    Having obtained access to the uncorrected proof, I first have to report that the first author is a Hack.

    …no, seriously, her name is Erica E. Hack, and I’m sure she’s thoroughly familiar with all the jokes. Studies are “led by” the last author, the one who does the least amount of work but provides the funding and/or the basic idea; and that is the mentioned Suzanne L. Tyas.

    Important quotes:

    Convent archives provided data on multilingualism, which had been collected in 1983 by an administrative questionnaire developed by the School Sisters of Notre Dame [45]. Participants reported the languages with which they had proficiency so that international mission placements could be determined. The number of languages reported ranged from one to five; because only a small proportion of participants spoke four or five languages, these categories were combined.

    Sounds like Latin was not included.

    Idea density was defined as the average number of ideas expressed per ten words. Grammatical complexity scores ranged from zero (one-clause sentences) to seven (sentences using multiple clauses and embedding).

    I wonder how many – most of them were/had been teachers – deliberately wrote simpler sentences than they could have.

    Immigration status (born in the United States versus other) was included [as a covariate] to adjust for its potential effects on multilingualism [10, 13, 15, 28, 29, 30, 33].

    Table 1:
    1 language: 87 participants
    2: 171
    3: 50
    4: 10
    5: 7
    Immigrant to USA: 18

    An interaction existed between the number of languages spoken and the other risk factors. For example, an APOEε4 carrier who was 85 years or older at baseline and who spoke four or more languages (dementia hazard probability = 0.04) had a risk of dementia similar to an APOEε4 non-carrier who was younger than 80 years at baseline and spoke only one language (dementia hazard probability = 0.03) (Fig. 1).

    there was no significant association of bilingualism or multilingualism with either idea density or grammatical complexity

    All covariates, including each of the 11 transition periods, were tested in the sensitivity analysis to determine their significance to dementia probability estimation. The most statistically suitable model included APOEε4 status, education, and a two-level idea density variable (i.e., first [lowest] quartile versus second, third, and fourth quartiles, which were combined given similar parameter estimates for the top three quartiles). Multilingualism was not significantly associated with dementia likelihood after adjustment for these variables (Table 4), although this may be due in part to the lower sample size for the sensitivity analysis.

    Sensitivity analyses investigating the influence of other measures of linguistic ability on the impact of multilingualism on dementia showed no significant association between dementia and any number of languages spoken, with the protective effect on dementia of speaking four or more languages weakened to nonsignificance in the presence of idea density. Thus, linguistic ability broadly was a significant predictor of dementia in our study. However, it was written linguistic ability (specifically idea density) rather than multilingualism that was the strongest predictor.

    In addition to the number of languages studied, past studies also vary in their measure of multilingualism. Our definition of multilingualism was not as stringent as in some of the studies which found bilingual advantages: we ascertained multilingual status through self-reports of languages spoken proficiently whereas other accounts of multilingual cognitive advantage have measured language proficiency through fluency testing or by having participants actively use the language(s) with which they claimed proficiency. The equal use of multiple languages every day (e.g., being “balanced” in many languages) was also not a requirement in our study. Use of more stringent definitions for multilingualism in some studies [9, 10, 12, 13] may explain why they found an association with dementia among those speaking two or more languages whereas we did not see any impact until our highest levels of multilingualism (four or more languages). It may also be that it is only these multilingual individuals who were actively using, or more likely to use, their multi-language capabilities in their daily life. That is, their job posting (location) and regular teaching duties may have been chosen specifically because they were highly capable in many different languages, and thus were placed into situations where they more regularly and actively made use of their linguistic abilities. This increased daily practice in use and coordination of multiple languages may have been the key to their development of cognitive resilience, over and above that of the participants who reported fluency in only two languages, and could explain why we only found protective effects for those speaking four or more languages.

    Overall, the variation in results calls the proposed mechanism of dementia protection by multilingualism into question: while multilingualism may bestow advantages in executive control upon a given individual, these advantages may not necessarily contribute to cognitive resilience. In contrast to little evidence of a protective effect of bilingualism in population-based studies, there is some evidence in these studies of a reduced risk of cognitive impairment and dementia in those speaking more than two languages. However, this is a highly selected population and individuals capable of speaking three or more languages (or four or more languages in our study) may be systematically different from those speaking one or two languages; it may be these traits rather than multilingualism that are associated with heightened cognitive resilience.

    incorporating idea density in the discrete-time survival analysis was expected to change the observed association between multilingualism and dementia: it did so, with the effects of multilingualism weakened in the presence of idea density. The lack of a significant association between written linguistic ability measures and multilingualism supports the separate effects of these factors. The influence on dementia of multiple linguistic measures and their inter-relationships thus warrants further exploration in studies of the association of multilingualism with dementia.

    Limitations of our study include the self-reported measure of multilingualism. Given that our investigation used secondary data collected years before the inception of the Nun Study, we did not have the option to objectively assess language proficiency, nor did we have data on other measures such as age at language acquisition. The questionnaire collecting data on multilingualism, however, was intended to facilitate future placements, including teaching positions abroad, and participants would therefore have presumably reported proficiency in only the languages in which they believed they could teach. In addition, a population-based study that used both self-report and objective measures of language ability found the same lack of association with dementia with either measure [29].

    What can I say? Science journalism is usually neither.

  15. David Eddyshaw says:

    Thanks, DM.

    Truly glad to see that the paper is indeed considerably more sensible than the more-than-commonly-incompetent reporting would suggest. If I were the (real) author, I’d be seriously pissed off by this.

    It’s not a bad heuristic to assume as a preliminary hypothesis that the reporter is at fault rather than the researcher. I should have remembered that …

    (Unfortunately, in my own line of work, quite a number of perfectly respectable researchers are ethically irresponsible in allowing deeply misleading crap to be put out by their press people in order to keep their public profile prominent. I see actual harm done to real people by this, and it colours my view of such practices quite a bit. Here the stakes are rather less, I guess.)

  16. David Eddyshaw says:

    Idea density was defined as the average number of ideas expressed per ten words. Grammatical complexity scores ranged from zero (one-clause sentences) to seven (sentences using multiple clauses and embedding)

    Both these measures (as I need tell nobody here) are very highly dependent on the particular language involved. Even within a single language, I think I could justify wildly different numbers of “ideas” for the exact same sentence. Is plurality an “idea”? Is “tense”? Is “definiteness”? I could mount good arguments for some of these being more than one idea. Is “width” one idea or two? How about “wideness”? or “being wide”?

    What counts as a clause? How many clauses are there in “I want to go home”? (The Cambridge Grammar makes it two.)

    I suspect that none of the authors has any significant linguistic expertise. Have they consulted anyone who does, DM?

  17. Stu Clayton says:

    Dementia is a small matter. The all-encompassing, debilitating risk is gullibility, in particular a faddish attraction to “studies”, here on dementia and languages. Everybody wants to be the Jane Fonda of cognitive resilience.

    Exercise your mind by learning German!

  18. David Eddyshaw says:

    Pfui! Kusaal has much more embedding than German. Dementia is consequently unknown among the Kusaasi.

    Jane Fonda? (Well, why not Jane Fonda, I suppose. Why not, indeed?)

  19. Jane Fonda the exercise maven, that is, not Jane Fonda the singer or Jane Fonda the political figure.

  20. Stu Clayton says:

    Nothing wrong with Jane Fonda. My point was that exercise, in fact any kind of physical or mental exertion, keeps your mind off things you can’t change and might otherwise worry about. Analyzing “studies” about dementia and language accomplishes the same goal, ditto studying Luhmann.

    When dementia comes, you won’t notice it, and Jane Fonda videos (or volumes of Luhmann) will have kept you fit until then.

    Apart from that, note the resemblance between the subject of this “study” and the 19C Anglophone practice of inculcating Latin and Greek into schoolboys in order to train their analytical faculties.

  21. David Eddyshaw says:

    @JC, Stu:

    Ah. Now I see.

    Intellectually, a wholly satisfying explanation. Yet I am left, somehow, disappointed.

  22. Idea density was defined as the average number of ideas expressed per ten words.

    To rescue something from this: is ‘idea density’ a term of art with a robust definition? Could there be words amongst those ten that don’t ‘express an idea’? Do we get examples of low-density ten-words vs high-density?

    How many ideas in “Buffalo buffalo buffalo buffalo buffalo”?

    As David E points out, there’s variation amongst languages/not least in what counts as a ‘word’. Then shouldn’t the measure be density per ten words as compared with the average in that language?

  23. Stu Clayton says:

    You’re onto something ! But in light of your buffalo example, I suggest density per ten different words. For the purposes of measurement I think we must assume that the number of ideas cannot be greater than the number of words, although it definitely can be less, even zero. Without this assumption, I see no clear connection between words and ideas. Of course for this too there is abundant empirical evidence.

  24. David Eddyshaw says:

    is ‘idea density’ a term of art with a robust definition?

    Presumably the paper itself references some such metric, and David M can tell us (unless the authors are so linguistically naive as not to realise that the idea is problematic at all.)

    I don’t know of any, but that proves nothing. There are vast areas of which I am completely ignorant. If such a thing exists, I would be fascinated (and can think of several applications already.)

  25. Stu Clayton says:

    Writings with a low idea density would be buoyant, so they can be used to operate airships.

  26. As I recall, when the Nun Study results on the correlation between subjects’ writing styles and propensities for dementia were first released (early this century), they used writing samples taken from the nuns’ work when they were relatively young. That there would be a correlation between the complexity of the language someone used when they were already old and their odds of incipient dementia is almost tautological. However, what was considered remarkable was that the linguistic complexity of a nun’s writing was correlated with if and when she would develop dementia decades later.

  27. Aha! I thought this sounded familiar. Language Log covered the nun study and idea density dating back some 20 years http://itre.cis.upenn.edu/~myl/languagelog/archives/001686.html

    You can tell Liberman is underwhelmed. “This may not be a joke.” is what I’d call damning with faint praise.

  28. Is Jane Fonda really a singer? I remember (back on topic) she was married to Ted Turner, about whom I haven’t heard anything for years.

    Back on topic again, according to the BBC, dementia is an umbrella term, like cancer.

    Specific symptoms will depend on the parts of the brain that are damaged and the disease that is causing the dementia

    Alzheimer’s disease is by far the most common of the diseases that cause dementia. Others include vascular dementia, dementia with Lewy bodies, fronto-temporal dementia, Parkinson’s disease dementia, amyotrophic lateral sclerosis and the newly discovered Late.

    So multilingualism would in any case only reduce the risk in those diseases that affect the bits of the brain associated with language (though perhaps it’s all of them).

  29. @AJP Crown: There are some brain regions that are more strongly associated with language than others. (Notably, language is heavily lateralized*, with more language processing occurring in the left hemisphere than in the right**.) However, there does not appear to be any part of the cerebrum that does not have at least some involvement in language. A lesion on any part of the cerebrum can lead to language problems, although the typical severity does depend on the location. (This is also true of memories, which are not localized to any specific brain regions.)

    * There was another word I was reaching for, to denote a mental faculty that is localized in one hemisphere, but I could not remember it. Lateralized means the right thing, but I do not particularly care for the way it sounds.

    ** Popular understanding of right hemisphere versus left hemisphere differences is often depressingly bad. I remember reading a profile of someone I respected, who talked about her need to sometimes delve heavily into what he called “right brain activities,” especially creative writing (which is actually about as left-brain localized as a high-level activity can be). More subtly, I remember the 1965 story by Fred Saberhagen, “What T and I Did,” which relies for its premise on a misunderstanding of how the visual system works. The optic nerves from the eyes do not have the left eye reporting to the right brain hemisphere and vice versa (as it works for the other sensory and motor neurons). Instead, the left half of each eye’s visual field is reported to the right brain, and the right half of the visual field goes to the left brain.

  30. Goodness, Brett. How interesting. I wonder if (say) visual memories or smell memories are more localised.
    I suppose one of the advantages of electrical wiring is that as long as it connects at both ends its layout doesn’t always have to appear rational. The eye thing is complicated by the retinal image being upside-down and back-to-front to start with though of course the brain works with electrical nerve impulses rather than images, at least sometimes. That right & left side of the brain discussion was a popular book topic during the 1970s; I’m glad it’s ended, or at least dwindled.

  31. Stu Clayton says:

    A commemorative plaque should be put up: “Right/Left Brain Confusion reigned here from 1970 to 2000”. But where ? On the right side, I would think. Or possibly on the left and right on alternate days, with electrical discharges lighting the way. It’s such a silly, confused topic of general discussion.

  32. David Marjanović says:

    I suspect that none of the authors has any significant linguistic expertise. Have they consulted anyone who does, DM?

    The authors are are the School of Public Health (1st, 4th and last authors), the Department of Statistics and Actuarial Science (2nd) and the Department of Psychology (3rd) of the University of Waterloo, Ontario.

    Autobiographical essays written by participants in early adulthood (18 to 32 years of age; mean 22 years) were coded to obtain measures of English written language skills [37]: idea density [47] and grammatical complexity [48]. Idea density was defined as the average number of ideas expressed per ten words. Grammatical complexity scores ranged from zero (one-clause sentences) to seven (sentences using multiple clauses and embedding). Mean idea density and grammatical complexity scores were calculated for each participant based on the final ten sentences of each autobiography, ranked within each convent, and divided into quartiles. Only 180 members of the original Nun Study population provided handwritten autobiographies; therefore, a sensitivity analysis using a subset of participants with these data was performed to supplement the main analyses.

    [37] Snowdon DA, Kemper SJ, Mortimer JA, Greiner LH, Wekstein DR, Markesbery WR (1996) Linguistic ability in early life and cognitive function and Alzheimer’s disease in late life. Findings from the Nun Study. JAMA 275, 528-532.
    [47] Kintsch W, Keenan J (1973) Reading rate and retention as a function of the number of propositions in the base structure of sentences. Cogn Psychol 5, 257-274.
    [48] Cheung H, Kemper S (1992) Competing complexity metrics and adults’ production of complex sentences. Appl Psycholinguist 13, 53-76.

    So, the answer is no, and whether that matters depends on the references. I haven’t tried to look them up, but [47] is explained in the linked LLog post.

    they used writing samples taken from the nuns’ work when they were relatively young

    Yes.

  33. David Eddyshaw says:

    Thanks, AntC. That’s illuminating.

    Looks like the complexity test is simply taken from the original study, relates specifically to English and is in fact a repurposing of an attempt to measure how difficult a text is to read and remember based on counting lexemes (including conjunctions but no other function words) per sentence.

    The extract from Snowdon (author of the earlier study) cited in LL seems to use somewhat idiosyncratic definitions of both “proposition” and “utterance.”

    It does indeed look like the way to increase such “complexity” is to destrunk aggressively, though. Mark Liberman was way ahead of me there.

  34. David Eddyshaw says:

    Thanks, David M, too.

    The Cheung paper is actually accessible. It’s quite interesting; it’s the source of the bits about embedding causing difficulty for comprehension and recall. They talk about this in the context of limitations on working memory capacity, which (a) makes sense and (b) would of course be expected to correlate with other measurements of cognitive ability like digit span.

    It looks more solid than the Kintsch stuff. James Joyce (quoted in the LL post) was obviously ahead of the game: not only did he model his style on sound Kintschian complexity principles, but he gives the man a shout-out:

    Come up, Kintsch. Come up, you fearful Jesuit …

  35. Brett wrote: “Instead, the left half of each eye’s visual field is reported to the right brain, and the right half of the visual field goes to the left brain.”

    Indeed so. Two and a half years ago after a major surgery, my mother suffered a stroke that caused a right visual field cut (homonymous hemianopsia). During her subsequent hospitalizations and other medical treatment, most of the nurses and shockingly large numbers of the doctors have had no clue what that is.

    For the medical techs, we always have to simplify it to “she can’t see you ‘over there’”, because explaining any more fully loses them.

  36. Quite a good use of homonymous.

  37. Instead, the left half of each eye’s visual field is reported to the right brain, and the right half of the visual field goes to the left brain.

    Indeed, that’s the way I learned it: the left visual field is processed by the right half, the right visual field by the left half. I never really noticed the discrepancy between these two accounts. Chalk it up to being very non-visual.

  38. David Eddyshaw says:

    This happens because the two optic nerves join up and then separate again (under new names) just under the pituitary gland, and the nerve fibres coming from the nose-side of the retina (which sees out to the sides) cross over to the other side at that point. The fibres are sorted by visual-field side before they actually get to the brain.

    https://en.wikipedia.org/wiki/Optic_chiasm

    The field loss is on the same side as the loss of power in the limbs when the stroke affects both movement and sight. It’s not just vision that’s back-to-front in the brain (as it were.)

    It’s quite common when half the brain is damaged by a stroke for the person still to be able to see both sides, but not both at once. They will be able to see that you are holding up five fingers in the right field, or five fingers on the left, but if you hold up all ten fingers they’ll say “five.” It’s also common for the patient not to be able to tell subjectively that they’ve lost half the field of vision; the more self-aware will deduce the fact from the way they keep knocking things over or bumping into things.

  39. One is challenged to come up with a string of ten words that conveys zero ideas. They’d have to be real words that people would be expected to have encountered in normal life, or else it’s cheating. Long verbal forms like “would be expected to have encountered” certainly reduce the idea density, but not to zero.

  40. David Eddyshaw says:

    Brexit means Brexit. Brexit means Brexit. Brexit means Brexit. Brexit …

  41. David Eddyshaw says:

    I think the difficulty is coming up with a definition of “idea” which actually means anything much at all in a linguistic context. Snowdon’s misapprehension that “proposition” can be used for this is extraordinarily naive; reducing real languages to sets of discrete “propositions” is simply not possible. If people think they’ve done it, it’s because they simply haven’t noticed the problems, and probably are completely unacquainted with the linguistic and philosophical prior art. Life scientists seem to be prone to this …

    Where’s the proposition in “Go away and never come back” ?

  42. The absolute record for meaninglessness belongs, of course, to the Soviet propaganda.

    “The economy must be economic” (c) Brezhnev

  43. David Eddyshaw says:

    Actually, this (and our previous discussion about information density in language) reminded me of the notion of Linguistic Primes (which JC knows all about.) If you were really going to make a serious project of studying information density in language, you would need to have some robust way of decomposing lexemes into more basic meaning units. I think that would actually be the easy part; you’d also need to have some universal cross-linguistic framework for classifying how meaning intersects with morphology and syntax. How much meaning is there in a dative plural flexion? in an obviative? in an evidential ending? How much meaning is conveyed by putting the object before the subject in Latin? You’d need a rigorous quantification of semiotics. Good luck with that …

  44. I think the whole idea of “basic meaning units” is incoherent. As a young math major getting interested in linguistics, I had the dream of mathematically analyzing language, but I eventually realized it was impossible, an attempt to square the circle. The kinds of meaning inherent in language (which can be expressed phonetically, lexically, morphologically, syntactically, by allusion, by quotation, by juxtaposition…) have nothing whatever to do with the kinds of “meaning” dealt with by science and mathematics, except in the trivial sense that language-using humans live in a world which they try both to express in language and to analyze scientifically.

  45. And if we take dementia to involve lack of correspondence of ideas to reality, and assume that my awareness of the irreducibility of language to mathematics was aided by my knowing different languages, then truly we can say that multilingualism helps stave off dementia.

  46. David Eddyshaw says:

    In the much more narrow context of the Nun Study (great name, whatever else) you could after all get sensible figures for frequency of embedding in their youthful autobiographies in English; you could draw up a consistent list beforehand of English constructions that were to count as embedding for this purpose, and apply the list in an objective way. It seems very likely that this could serve as a meaningful baseline test for cognitive abilities like working memory capacity, and that it might correlate with the risk of dementia further down the line.

    This may indeed be pretty much what the researchers did, though there doesn’t seem to be any detail available about the exact techniques they used, perhaps because they didn’t appreciate that such issues are not actually straightforward. It wouldn’t necessarily vitiate the result even if the lead researchers misunderstood just what they were measuring, so long as they were in fact objectively performing assessments which could be independently shown to reflect some aspect of general cognitive ability.

    As far as the Hack/Tyas paper goes, it seems to boil down to:

    “The Nun Study suggests people who start out above average in at least the verbal aspects of intelligence are less likely to become demented; we wondered if people in this study who said they knew several languages turned out to be particularly less likely to become demented and went back over the data to see. The evidence that this has any effect independent of verbal intelligence in general turned out to be surprisingly weak, compared with what other studies seem to suggest.”

  47. David Eddyshaw says:

    my awareness of the irreducibility of language to mathematics was aided by my knowing different languages

    Knowing several languages certainly helps to stave off Chomskyism, though it does not (alas) confer absolute protection.

  48. I was going to amaze you all by revealing exactly how many participants were quadrilingual, but DM (8:32pm) has already given the numbers, so you might have suspected cheating. Nevertheless, it was obvious to me that the number was 17, because the proportion of quadrilingual nuns in a group of 325 would naturally be well under 10%, and the only n less than 32, that would satisfy the condition that 1/n rounds off to .06 is . . . 17. It turns out that the one demented quadrilingual (or quinquelingual?) nun was 1/17 of 1/15 (or 6% of 5%) of the total. Margin of error in this case? Substantial, but unquantifiable, at least by me. I’m no statistician.

  49. David Eddyshaw says:

    It must surely be a deathly insult in some fiery South American dialect:

    “Son of a demented quadrilingual nun!”

  50. David Eddyshaw says:

    The last (well, only) group of nuns whose hospitality I have enjoyed were all quadrilingual. (Spanish, French, English, Gulimancéma.) They were excellent people, and I am glad to think that they have probably not become demented.

    There is (or was) also a well-regarded restaurant in Ouagadougou called L’Eau Vive which has (actual) nuns as waitresses. They break off to sing Ave Maria now and again. I don’t think speaking four languages is a job requirement for them, though.

  51. I had been wondering why I always feel slightly less demented after reading a languagehat post.

  52. Gulimancéma

    I find this is the language known (vaguely) to me as Gourmanché.

  53. This is the totality of the description in that article:

    All nouns in the language are classified into eight classes, identified by their prefixes and suffixes in both singular and plural. All mass nouns, states of existence, languages, for example, begin with the prefix mi– and end with the suffix –ma (that is, they take the circumfix mi—ma), as in blood (misuama), water (minyima), sand (mitambima), fire (mifantama), existence (miyema), state of being crazy (migadima), Gourmantché language (migourmantchema). All trees have a set of circumfixes bu—bu and i—di in the singular and plural, as in busaabu (shea tree) and isaandi (shea trees).

    A very selective set of facts!

  54. Of course, compared to the other Wikipedia articles (even French), which have zero description (at most a list of the letters used in transcribing it), it’s a veritable cornucopia.

  55. David Eddyshaw says:

    Gourmanché is the largest (by number of speakers) of the Gurma languages, a major branch of Oti-Volta but not the one that Kusaal belongs to. It’s fairly closely related to Moba (which spreads a little into Ghana.) It’s the major language of the more easterly bits of Burkina Faso, where I did quite a lot of outreach work.

    What the Wikipedia article is attempting to describe is that beside the usual Gur noun-class suffix thing (e.g. biga “child” = Kusaal biig), nouns often have a proclitic agreeing prefix, which is really rather more like an article than part of the noun morphology itself: gibiga “the child.” The verb aspect flexion system is much more unpredictable than in Western Oti-Volta languages like Kusaal: you basically just have to learn the perfective and imperfective forms for each verb (bad as Russian.) The inherited system of multiple grammatical genders based on noun classes is very much alive and well, as in all of Oti-Volta apart from Western, where most languages have dropped it altogether and even those that haven’t have drastically reduced the number of agreement genders.

    Although this is not accepted wisdom (yet), my suspicion is that Gurma and two of the so-called Eastern Oti-Volta languages in Bénin (which are probably only a geographical, not genetic, subgroup) make one of two primary branches of Oti-Volta, all other Oti-Volta languages forming the other.

  56. Maybe you could add at least a few sentences to the article to provide a little context?

  57. David Eddyshaw says:

    I will. I’m no expert on Gulimancéma, but I suppose I might have to do until one comes along.
    I’ve never seen a proper full grammatical description, though there are pretty good ones of its close-ish relatives Moba and Konkomba in French (both PhD theses written by native speakers.) I did see some helpful photocopied paedagogical stuff on Gulimancéma produced by and for missionaries when I was in the area. And there’s a quite decent Gulimancéma-French dictionary.

  58. So there’s something you can reference to keep the Wikicops off your back. Excellent!

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