Bilingualism Is Associated with a Delayed Onset of Dementia but Not with a Lower Risk of Developing it: a Systematic Review with Meta-Analyses.

Some studies have linked bilingualism with a later onset of dementia, Alzheimer's disease (AD), and mild cognitive impairment (MCI). Not all studies have observed such relationships, however. Differences in study outcomes may be due to methodological limitations and the presence of confounding factors within studies such as immigration status and level of education. We conducted the first systematic review with meta-analysis combining cross-sectional studies to explore if bilingualism might delay symptom onset and diagnosis of dementia, AD, and MCI. Primary outcomes included the age of symptom onset, the age at diagnosis of MCI or dementia, and the risk of developing MCI or dementia. A secondary outcome included the degree of disease severity at dementia diagnosis. There was no difference in the age of MCI diagnosis between monolinguals and bilinguals [mean difference: 3.2; 95% confidence intervals (CI): -3.4, 9.7]. Bilinguals vs. monolinguals reported experiencing AD symptoms 4.7 years (95% CI: 3.3, 6.1) later. Bilinguals vs. monolinguals were diagnosed with dementia 3.3 years (95% CI: 1.7, 4.9) later. Here, 95% prediction intervals showed a large dispersion of effect sizes (-1.9 to 8.5). We investigated this dispersion with a subgroup meta-analysis comparing studies that had recruited participants with dementia to studies that had recruited participants with AD on the age of dementia and AD diagnosis between mono- and bilinguals. Results showed that bilinguals vs. monolinguals were 1.9 years (95% CI: -0.9, 4.7) and 4.2 (95% CI: 2.0, 6.4) older than monolinguals at the time of dementia and AD diagnosis, respectively. The mean difference between the two subgroups was not significant. There was no significant risk reduction (odds ratio: 0.89; 95% CI: 0.68-1.16) in developing dementia among bilinguals vs. monolinguals. Also, there was no significant difference (Hedges' g = 0.05; 95% CI: -0.13, 0.24) in disease severity at dementia diagnosis between bilinguals and monolinguals, despite bilinguals being significantly older. The majority of studies had adjusted for level of education suggesting that education might not have played a role in the observed delay in dementia among bilinguals vs. monolinguals. Although findings indicated that bilingualism was on average related to a delayed onset of dementia, the magnitude of this relationship varied across different settings. This variation may be due to unexplained heterogeneity and different sources of bias in the included studies. Registration: PROSPERO CRD42015019100

Age of second language acquisition affects nonverbal conflict processing in children : an fMRI study

Background: In their daily communication, bilinguals switch between two languages, a process that involves the selection of a target language and minimization of interference from a nontarget language. Previous studies have uncovered the neural structure in bilinguals and the activation patterns associated with performing verbal conflict tasks. One question that remains, however is whether this extra verbal switching affects brain function during nonverbal conflict tasks. Methods: In this study, we have used fMRI to investigate the impact of bilingualism in children performing two nonverbal tasks involving stimulus-stimulus and stimulus-response conflicts. Three groups of 8-11-year-old children - bilinguals from birth (2L1), second language learners (L2L), and a control group of monolinguals (1L1) - were scanned while performing a color Simon and a numerical Stroop task. Reaction times and accuracy were logged. Results: Compared to monolingual controls, bilingual children showed higher behavioral congruency effect of these tasks, which is matched by the recruitment of brain regions that are generally used in general cognitive control, language processing or to solve language conflict situations in bilinguals (caudate nucleus, posterior cingulate gyrus, STG, precuneus). Further, the activation of these areas was found to be higher in 2L1 compared to L2L. Conclusion: The coupling of longer reaction times to the recruitment of extra language-related brain areas supports the hypothesis that when dealing with language conflicts the specialization of bilinguals hampers the way they can process with nonverbal conflicts, at least at early stages in life

No evidence for reduced Simon cost in elderly bilinguals and bidialectals

We explored whether a bilingual advantage in executive control is associated with differences in cultural and ethnic background associated with the bilinguals’ immigrant status, and whether dialect use in monolinguals can also incur such an advantage. Performance on the Simon task in older non-immigrant (Gaelic-English) and immigrant (Bengali, Gujarati, Hindi, Malay, Punjabi, Urdu-English) bilinguals was compared with three groups of older monolingual English speakers, who were either monodialectal users of the same English variety as the bilinguals or were bidialectal users of a local variety of Scots. Results showed no group differences in overall reaction times as well as in the Simon effect thus providing no evidence that an executive control advantage is related to differences in cultural and ethnic background as was found for immigrant compared to non-immigrant bilinguals, nor that executive control may be improved by use of dialect. We suggest the role of interactional contexts and bilingual literacy as potential explanations for inconsistent findings of a bilingual advantage in executive control

Language sample analysis for Spanish speakers

textThe purpose of this project was to develop a Spanish language sample analysis (LSA) scoring procedure for English-Spanish bilinguals used to guide clinicians in developing language goals and monitoring progress on those goals. A Spanish LSA procedure was created and was tested on 20 typically developing and 16 language impaired English-Spanish bilinguals. Each utterance of each language sample was analyzed for correct and attempted use of the 20 grammatical forms selected for the LSA procedure. Based on the results, a preliminary profile of impairment was established. It showed that Relative Clauses, Infinitive Clauses, Present Subjunctive, Third Person Plural Present and Preterit Indicative, Irregular Preterit Indicative, Indirect and Direct Object Clitics, Imperfect, and Plural Nouns were the most problematic forms for English-Spanish bilinguals with LI. Clinical implications of these findings are discussed.Communication Sciences and Disorder

Frequency drives lexical access in reading but not in speaking: the frequency-lag hypothesis

To contrast mechanisms of lexical access in production versus comprehension we compared the effects of word frequency (high, low), context (none, low constraint, high constraint), and level of English proficiency (monolingual, Spanish-English bilingual, Dutch-English bilingual) on picture naming, lexical decision, and eye fixation times. Semantic constraint effects were larger in production than in reading. Frequency effects were larger in production than in reading without constraining context but larger in reading than in production with constraining context. Bilingual disadvantages were modulated by frequency in production but not in eye fixation times, were not smaller in low-constraint contexts, and were reduced by high-constraint contexts only in production and only at the lowest level of English proficiency. These results challenge existing accounts of bilingual disadvantages and reveal fundamentally different processes during lexical access across modalities, entailing a primarily semantically driven search in production but a frequency-driven search in comprehension. The apparently more interactive process in production than comprehension could simply reflect a greater number of frequency-sensitive processing stages in production

Asymmetric switch costs in numeral naming and number word reading: Implications for models of bilingual language production

One approach used to gain insight into the processes underlying bilingual language comprehension and production examines the costs that arise from switching languages. For unbalanced bilinguals, asymmetric switch costs are reported in speech production, where the switch cost for Ll is larger than the switch cost for L2, whereas, symmetric switch costs are reported in language comprehension tasks, where the cost of switching is the same for L1 and L2. Presently, it is unclear why asymmetric switch costs are observed in speech production, but not in language comprehension. Three experiments are reported that simultaneously examine methodological explanations of task related differences in the switch cost asymmetry and the predictions of three accounts of the switch cost asymmetry in speech production. The results of these experiments suggest that (1) the type of language task (comprehension vs. production) determines whether an asymmetric switch cost is observed and (2) at least some of the switch cost asymmetry arises within the language system

Phonological Factors Affecting L1 Phonetic Realization of Proficient Polish Users of English

Acoustic phonetic studies examine the L1 of Polish speakers with professional level proficiency in English. The studies include two tasks, a production task carried out entirely in Polish and a phonetic code-switching task in which speakers insert target Polish words or phrases into an English carrier. Additionally, two phonetic parameters are studied: the oft-investigated VOT, as well as glottalization vs. sandhi linking of word-initial vowels. In monolingual Polish mode, L2 interference was observed for the VOT parameter, but not for sandhi linking. It is suggested that this discrepancy may be related to the differing phonological status of the two phonetic parameters. In the code-switching tasks, VOTs were on the whole more English-like than in monolingual mode, but this appeared to be a matter of individual performance. An increase in the rate of sandhi linking in the code-switches, except for the case of one speaker, appeared to be a function of accelerated production of L1 target items

Late L2 Acquisition and Phonological Memory Development

The development of phonological memory, a subdivision of short term memory, is crucial to learning and analyzing sequences of sounds to form words and phrases. This process utilizes short term representation and rehearsal to allow for the eventual long term representation of language. Individuals learning more than one language must acquire even more of these language sequences than monolinguals. Previous research agrees that early Spanish-English bilinguals have superior phonological memory to monolinguals, however the impact of second language acquisition on phonological memory remains unknown. This study examined three groups of undergraduate participants studying Spanish as a second language including study abroad students (SA), students currently enrolled in a Spanish course at or above the 300-level (CE), and students not currently enrolled in a Spanish course (NE). Participants completed tests of phonological memory including digit span and sentence repetition at the beginning and culmination of an academic semester. Participants also provided demographic data, L2 acquisition information, and their frequency of language use so that changes could be calculated. Results revealed that CE students were superior during pretest, but during posttest SA and CE demonstrated comparable results. The NE students demonstrated consistently lower scores. These findings suggest that foreign language instruction may benefit phonological memory development, even in late acquisition of the second language. The possible role of years of formal language instruction will be discussed

Cognate facilitation effects in bilingual children of varying language dominance

A widely accepted theory is that bilinguals activate both of their languages regardless of which is in use. Though there is abundant research on this phenomenon in bilingual adults, less research has focused on bilingual children. Cognates (i.e., words that share meaning and sound across languages) have frequently been used to explore language co-activation. The present study investigates cognate facilitation effects in child bilinguals of varying language dominance. Spanish-English bilingual children between 6 and 10 years old performed a picture-naming task that included pictures of cognates and non-cognates. Children who were more English-dominant experienced larger cognate facilitation effects when producing words in their non-dominant language but not in their dominant language. In contrast, children with more balanced dominance did not experience cognate facilitation effects in either language. The findings from this study may have implications for the development of the bilingual lexicon.Psycholog

Towards a description of trilingual competence

Most studies involving trilingualism have been carried out within the theoretical framework of bilingualism research. No attempt has been made to delimit trilingualism as a concept in its own right, and often it has been assumed to be an extension of bilingualism. In young children, trilingual language acquisition largely follows the path of bilingual acquisition. With regard to language behavior there are again similarities, but certain differences can be observed. As an overview of studies of individual trilingualism, the present article aims to provide a framework for the discussion. Models of bilingual language competence serve as a starting point to an investigation of possible defining features of trilingual competence. Of particular interest are the pragmatic component of language competence; the trilingual's ability to make appropriate linguistic choices in monolingual/bilingual/ trilingual communication modes; and observed codeswitching. The question of how and when a trilingual's languages become activated or deactivated leads to a consideration of language processing and metalinguistic awareness. In the absence of research involving trilinguals, bilingual models are examined with a view to pointing out possible similarities and differences. It is suggested that these are both of a quantitative and qualitative kind, and therefore trilingual competence is distinct from bilingual competence