High Proficiency Bilinguals Research Articles

Neural networks for short-term memory for order differentiate high and low proficiency bilinguals

Short-term memory (STM) for order information, as compared to STM for item information, has been shown to be a critical determinant of language learning capacity. The present fMRI study asked whether the neural substrates of order STM can serve as markers for bilingual language achievement. Two groups of German–French bilinguals differing in second language proficiency were presented STM tasks probing serial order or item information. During order STM but not item STM tasks, the high proficiency group showed increased activation in the lateral orbito-frontal and the superior frontal gyri associated with updating and grouped rehearsal of serial order information. Functional connectivity analyses for order encoding showed a functional network involving the left IPS, the right IPS and the right superior cerebellum in the high proficiency group while the low proficiency group showed enhanced connectivity between the left IPS and bilateral superior temporal and temporo-parietal areas involved in item processing. The present data suggest that low proficiency bilinguals activate STM networks for order in a less efficient and differentiated way, and this may explain their poorer storage and learning capacity for verbal sequences.

Assessing the presence of lexical competition across languages: Evidence from the Stroop task

Do the lexical representations of the non-response language enter into lexical competition during speech production? This issue has been studied by means of the picture–word interference paradigm in which two paradoxical effects have been observed. The so-called CROSS-LANGUAGE IDENTITY EFFECT (Costa, Miozzo and Caramazza, 1999) has been taken as evidence against cross-linguistic lexical competition. In contrast, the so-called PHONO-TRANSLATION EFFECT (Hermans, Bongaerts, De Bot and Schreuder, 1998) has been interpreted as revealing lexical competition across languages. In this article, we assess the reliability of these two effects by testing Spanish–Catalan highly-proficient bilinguals performing a Stroop task. The results of the experiment are clear: while the cross-language identity facilitation effect is reliably replicated, the phono-translation interference effect is absent from the Stroop task. From these results, we conclude that we should be cautious when drawing strong conclusions about the presence of competition across languages based on the phono-translation effect observed in the picture–word interference paradigm.

Another look at cross-language competition in bilingual speech production: Lexical and phonological factors

How does lexical selection function in highly-proficient bilingual speakers? What is the role of the non-response language during the course of lexicalization? Evidence of cross-language interference was obtained by Hermans, Bongaerts, De Bot and Schreuder (1998) using the picture-word interference paradigm: participants took longer to name the picture when it appeared with a word phonologically related to the target's translation than when it was accompanied by a control (phono-translation interference). Here we report two picture-word interference experiments that explored whether the same pattern of interference is present for highly-proficient bilinguals producing speech in L2. The results of the two experiments partially replicate those of Hermans et al. (1998), revealing the reliability of the phono-translation effect. We discuss some possible loci of this effect during the lexicalization process, and its implications for models of bilinguals speech production.

On the autonomy of the grammatical gender systems of the two languages of a bilingual

In five experiments highly-proficient bilinguals were asked to name two sets of pictures in their L2: a) pictures whose names in the L2 and their corresponding L1 translations have the same grammatical gender value, and b) pictures whose names in the L2 and their corresponding L1 translations have different gender values. In Experiments 1, 2, and 3 Croatian-Italian speakers were asked to name the pictures in Italian by means of NPs in various experimental contexts. In Experiment 4A, Spanish-Catalan and Catalan-Spanish bilinguals were asked to name the pictures in Spanish, and in Experiment 4B, Italian-French bilinguals did so in French. The results of these experiments revealed no differences between same- and different-gender pictures. Furthermore, the performance of Italian, Spanish, and French monolingual speakers parallels that of bilingual speakers. However, a robust frequency effect was observed across experiments. This pattern of results supports the notion that the gender value of the words in the non-response language does not affect processing in the response language, and suggests that the two gender systems of a bilingual are functionally autonomous.

The role of age of acquisition and language usage in early, high-proficient bilinguals: an fMRI study during verbal fluency.

We assessed the effects of age of acquisition and language exposure on the cerebral correlates of lexical retrieval in high-proficient, early-acquisition bilinguals. Functional MRI was used to study Spanish-Catalan bilinguals who acquired either Spanish or Catalan as a first language in the first years of life. Subjects were exposed to the second language at 3 years of age, and have used both languages in daily life since then. Subjects had a comparable level of proficiency in the comprehension of both languages. Lexical retrieval with the verbal fluency task resulted in the well-established pattern of left hemispheric activation centered on the inferior frontal region. The effect of age of acquisition was assessed by dividing the subjects into two groups, on the basis of the language acquired first (Catalan-born or Spanish-born bilinguals). Functional comparisons indicated that less extensive brain activation was associated with lexical retrieval in the language acquired earlier in life. The two groups were also different in language usage/exposure, as assessed with a specific questionnaire; in particular, the exposure to the second language (Spanish) was less intensive in the case of Catalans. This was reflected in a significant interaction, indicating a more extensive activation in Catalans during production in Spanish. Overall, these results indicate that, during a production task, both age of acquisition and language exposure affect the pattern of brain activation in bilinguals, even if both languages are acquired early and with a comparable level of proficiency.

Acoustic Scanning and Syntactic Processing Three Reading Experiments — First and Second Language Learners

To test the acoustic scanning hypothesis for reading, three experiments were conducted with monolingual and bilingual subjects. Ss performed a crossout task, cancelling letters in a text as they read it for comprehension. Letters remaining uncancelled were then analyzed. In Experiment 1, letters were frequently unmarked in function words, words which are highly predictable since they serve primarily to mark case relationships between content words. Changing passage difficulty did not effect the ratio of letters marked in content and function words. No significant difference was found between monolingual and highly-proficient bilinguals. In Experiments 2 and 3, Anglos marked letters in content words and especially in syllables receiving primary or secondary stress, leaving uncancelled those in unstressed function word position. Less proficient foreign students marked almost equal numbers of letters in function and content words and in stressed and unstressed positions. They also marked letters in digraphs as frequently as in single grapheme to phoneme correspondences. In the experiments, Anglos used acoustic scanning along with prediction of syntax for the task; less proficient bilinguals did not. The relationship between acoustic scanning and syntactic processing is discussed and suggestions for classroom application of the findings are included.