To be between the devil and the deep blue sea. He really does ... The wolf may lose his teeth, but never his nature. A word is ... An idle brain is the devil's shop.
BRAIN
AND
LANGUAGE
39, 69-89 (1990)
Cerebral Lateralization in Simultaneous Interpretation FRANCO FABBRO Istituto
per l’lnfunziu
“Burlo
Gorofolo.”
Trieste
LAURA GRAN Scuola Superiore
di Lingue Moderne per Interpreti
e Truduttori,
Universitd
di Trieste
AND GIANPAOLO BASSO AND ANTONIO BAVA Istituto
di Fisiologicr,
Uniwrsitir
di Trieste
Cerebral asymmetries for LI (Italian), L2 (English), and L3 (French, German, Spanish, or Russian) were studied, by using a verbal-manual interference paradigm, in a group of Italian right-handed polyglot female students at the Scuola Superiore di Lingue Moderne per Interpreti e Traduttori (SSLM-School for Interpreters and Translators) of the University of Trieste and in a control group of right-handed monolingual female students at the Medical School of the University of Trieste. In an automatic speech production task no significant cerebral lateralization was found for the mother tongue (Ll) either in the interpreting students or in the control group; the interpreting students were not significantly lateralized for the third language (L3), while weak left hemispheric lateralization was shown for L2. A significantly higher degree of verbal-manual interference was found for LI than for L2 and L3. A significantly higher disruption rate occurred in the meaning-based mode of simultaneous interpretation (from L2 into LI and vice versa) than in the word-for-word mode (from L2 into LI and vice versa). No significant overall or hemispheric differences were found during simultaneous interpretation from Ll into L2 or from L2 into Ll. cc) 19~0 Academic Press, Inc.
INTRODUCTION
The left hemisphere’s dominance for language in most right-handed monolinguals is well-known. Following a left-hemisphere lesion a monolingual patient may display the symptoms of an aphasic syndrome with Requests for reprints should be sent to Dr. Franc0 Fabbro, lstituto per I’Infanzia, Div. Neuropsichiatria Infantile, Via dell’Istria, 65/l, 34100 Trieste, Italy. 69 0093-934x/90
$3.00
Copyright 0 1990 by Academic Pres, Inc. All rights of reproduction in any form reserved.
70
FABBRO
ET AL.
expressive impairments, receptive impairments, anemic impairments, impairments of repetition, global impairments, agraphia, or alexia (TaylorSat-no, 1981). Polyglot patients may suffer other specific deficits: (a) inability to translate, (b) regression (a language that initially improved deteriorates as a second language improves), (c) impairments in switching from one language to another (patients speak a certain language inappropriately), (d) mixing of elements of two languages, (e) discrepancy in impairment or recovery (either in degree or in type), (f) spontaneous translation (immediate and unsolicited translation of one’s own utterances into a second language), (g) alternate antagonism (in alternation one language may become inaccessible), (h) paradoxical translation [patients may speak the mother tongue (Ll) better than the second language (L2) one day, may be able to name the objects surrounding them in Ll and translate these words into L2-in which they are anemic on that same day-but may be unable to translate L2 words into Ll]; see Gastaldi, 1951; Albert and Obler, 1978; Paradis, Goldblum, and Abidi, 1982; Perecman, 1984. Research on polyglot aphasics raised the more specific question of how the representation of languages is organized in the brain. Paradis (1987) proposed four different hypotheses: (1) The Extended System Hypothesis. As languages are undifferentiated in their representation, they are not substantially different from each other in their cerebral organization: the polyglot language system simply contains more morphemes and more syntactic rules. Several elements are in favor of this hypothesis, i.e., accent, prosody, vocabulary, and rules of a specific language that are used while speaking another language. Parallel recovery of two or more languages is another support to this hypothesis. (2) The Dual System Hypothesis. The elements of each language are stored separately in a system of connections independent of each other. Selective recovery of a language is in accord with this second hypothesis. (3) The Tripartite System Hypothesis. Some elements of the languages known to a subject are represented in common neuronal structures, other elements in different structures. Several studies with electric cortical stimulation on patients who were undergoing neurosurgical operations showed that electric stimulation in certain areas could selectively impair one language at a time, whereas stimulation in other areas could impair more than one language at a time. These studies were carried out on patients who only knew Indo-European languages (Ojemann & Whitaker, 1978) and on patients who knew Indo-European and Asian languages (Rapport, Tan, & Whitaker, 1983). Moreover, Chernigovskaya, Balonov, and Deglin (1983) examined by means of a unilateral electroconvulsive technique a bilingual psychiatric patient who had started learning his second language (L2) after 7 years of age. They proposed that the right hemisphere is concerned with the formation of deep semantic structures of the native
CEREBRAL
LATERALIZATION
IN POLYGLOTS
71
language (Ll), while the left hemisphere is responsible for the formation of second language (L2) deep structures and of surface structures of both languages. (4) The Subset Hypothesis. Even though the different languages are represented in different neuronal structures they form several subsystems of a larger system which includes all the known languages. One of the main questions arising in connection with the studies on polyglot aphasics regards the role of the right hemisphere in polyglots. Initially, several studies reported a greater percentage of crossed aphasia following right-hemisphere lesions both in bilingual and polyglot righthanders (lo-15%) as opposed to monolinguals (2%); see Obler, Albert, and Gordon, 1975; Albert and Obler, 1978. These data were not corroborated by more recent studies on a vast population of bilingual subjects (Vaid, 1983; Paradis, 1987). For example, in a population of 31 aphasic polyglots and 57 aphasic monolinguals Chary (1986) found that right-hemisphere lesions caused aphasia in 13% of right-handed polyglots and 12% of right-handed monolinguals. The number of studies carried out on this topic so far is insufficient to conclude this debate. There is general agreement among researchers in the neuropsychology of bilingualism and polyglossia on the definition of several factors that affect the cerebral organization of the languages known to a person (Albert & Obler, 1978; Vaid, 1983; Vaid, 1986; Paradis, 1987). The age ofacquisition of the second (L2) and third (L3) language (and, possibly, of other languages) is one of these determinant factors. The earlier the second language is acquired (usually before 6 years of age) the more compact its cerebral organization is (compound bilingualism), whereas later acquisition of languages (generally after lo-14 years of age) is likely to determine a rather separated language organization (coordinate bilingualism). Another important factor is sex; in fact, righthanded women have a more symmetric representation of linguistic functions than men, and this is also reflected in their neuroanatomy (Trevarthen, 1984; Vaid, 1983). The question is whether or not a certain symmetry in the neural representation of linguistic functions facilitates the acquisition of several languages. The level of second/third language projiciency is another important factor, and it must be very high if people speaking more than one language are to be considered real bilinguals or polyglots. As polyglots, the subjects selected for our experimental studies fluently understand, speak, think in, as well as read and write, the different known languages. Cerebral organization may be influenced by another factor, namely the structural distances between languages (Paradis, 1987). Two different languages, with very few or no elements in common (e.g., Italian and Chinese) are regarded as distant languages and may be more separately represented in the brain than two closely related languages (e.g., Catalan and Spanish). Another debated factor is the manner of second language
72
FABBRO
ET AL.
acquisition (formal or informal; Albert & Obler, 1978; Vaid, 1983). Finally, even individual factors are worth considering: hand preference, cognitive strategies normally adopted by the subject, and emotional factors. As regards other methodological aspects to consider before carrying out an experiment, see Obler, Zatorre, Galloway, and Vaid (1982); Green and Vaid (1986). In the last 20 years numerous neurophysiological and neuropsychological experimental studies have been conducted to investigate the cerebral representation of languages in bilingual and polyglot subjects. Using neurophysiological experimental studies, Rogers, TenHouten, Kaplan, and Gardiner (1977) found in a population of Hopi-English bilingual children a greater activation of the right hemisphere while the children were listening to stories in Ll. A similar study was carried out by TenHouten (1981) on Chinese-English bilingual adults: by means of an EEG it was shown that the cerebral representation of L2 was more symmetric than that of Ll. Genesee, Hamers, Lambert, Mononen, Seitz, and Starck (1978) examined the recognition of words in Ll and L2 in three groups of French-English bilinguals (infant bilinguals, childhood bilinguals, and adolescent bilinguals). Adolescent bilinguals were quicker in processing the whole task and seemed to rely more on a right hemisphere-based strategy. To perform the task the different groups seemed to resort to different strategies. Dichotic listening studies have also been conducted to study hemispheric lateralization in bilinguals and polyglots. A few studies with consonant-vowel stimuli carried out on Navajo-English adult bilinguals (Scott, Hynd, Hunt, & Weed, 1979) and on Crow-English bilingual children (Vacate, 1984) showed a greater representation of linguistic functions in the right hemisphere compared to control groups. In a study on English-French bilingual adults, with acquisition of L2 after 10 years of age and a high level of proficiency in this language, Albanese (1985) found a greater participation of the right hemisphere in linguistic functions. Galloway and Scarcella (1982) studied cerebral lateralization of Ll and L2 in a group of Mexican-born men who were in the initial stage of acquiring English informally. For both languages the superiority of the right ear (left hemisphere) was evidenced. A similar result was achieved also by Soares (1982), who studied a group of PortugueseEnglish bilingual adults. Recently Fabbro, Gran, and Bava (1987a) studied the hypothesis of modification in cerebral laterality (Ll Italian, L2 English) during intensive academic training in the second language. Three groups of female right-handed university students with no history of left handedness were tested. The first group consisted of 12 first-year students at the Scuola Superiore di Lingue Moderne per Interpreti e Traduttori (SSLM-School for Interpreters and Translators) of the University of Trieste; the second group was formed by 12 fourth-year students of
CEREBRAL
LATERALIZATION
IN POLYGLOTS
73
conference interpreting at the SSLM and the control group was made up of 12 third-year students at the Medical School, University of Trieste. All the tested students were of Italian mother tongue and had begun to study their second language after 1I years of age. Most subjects of the first two groups understood and spoke a third language, though not the same one in all cases. The experimental technique used was dichotic listening to numbers in the interlingual paradigm (Kimura, 1961; Albanese, 1985). The three groups showed statistically significant differences in performing the task required. The group of first-year SSLM students revealed right-ear advantage in recalling numbers in both languages and a significantly higher score in recalling numbers in English. Fourth-year students showed the expected right-ear advantage in both languages and a significant left-ear superiority in reporting numbers in English as compared to Italian numbers. The only significant difference in the control group was the expected right-ear advantage in the number of digits recalled. This study revealed constant lateralization of the mother tongue (Ll) in the left hemisphere, which remained substantially unchanged during the acquisition of L2. Moreover, particularly in the fourth-year students, an increased left-ear participation in the processing of L2 was found. Tachistoscopic experimental studies have also provided useful findings on cerebral lateralization for languages. Bentin (1981) administered to Israeli students (aged 12-13) with a modest knowledge of English a tachistoscopic test with the presentation of words in Hebrew and English. In the first session of the experiment he found a superiority of the left visual field (right hemisphere) for English words, whereas in the second session the right visual field (left hemisphere) turned out to be superior. Shanon (1982) studied three groups of subjects: Israelis with a good knowledge of English, Anglo-Saxons with a good knowledge of Hebrew, and full bilinguals of these two languages. Presenting words in Hebrew and in English vertically, he found a right visual field advantage in both languages in all groups. The second language seemed to be less lateralized than the first. Sewell and Panou (1982, 1983) examined English-French and English-German bilinguals (acquisition of L2 in early adolescence) and found that bilinguals, like the control group and deaf subjects, showed a right visual field (left hemisphere) superiority which was significantly greater in Ll than in L2. In a tachistoscopic test Yoshizaki and Hatta (1987) presented Hebrew words to Japanese subjects without finding any superiority in either hemisphere. Learning the pronunciation of these words, however, led to the superiority of the right visual field. The authors drew the following conclusions: (1) hemisphere involvement in cognitive processing appears to be not solid but rather plastic; (2) learning experience may affect laterality differences. Vaid (1987) studied the asymmetries in the visual fields for rhyme and syntactic category
74
FABBRO
ET AL.
judgment. The results showed that early bilinguals use semantic strategies, whereas late bilinguals appear to have acquired increased sensitivity to surface characteristics of words (Genesee et al., 1978; Vaid & Lambert, 1979). Using the verbal-manual interference paradigm, Sussman, Franklin, and Simon (1982) studied hemispheric specialization in bilinguals who knew different languages and belonged to different age groups. A fingertapping test method (Kinsbourne & Cook, 1971) was used to study language lateralization. This technique consists of a verbal-manual interference paradigm, based on the concept of cerebral functional distance. This theory suggests that the degree of interference will be inversely related to the functional distance between the cerebral centers controlling verbal production and right/left hand movement. A group of 40 righthanded male bilinguals was compared to 40 right-handed male monolinguals. The monolingual subjects showed a highly asymmetrical effect of manual-verbal interference with a 12.1% right-hand interference and a 1.73% left-hand interference. The bilinguals speaking in their native language (Ll) revealed less asymmetry, as the right hand had a mean interference of 11.64% compared to 4.99% for the left hand. Asymmetry decreased even further for L2 (right hand = 12.97%, left hand = 9.47%). Right-hand disruption was similar in the control group and in bilinguals (both for Ll and L2), while left-hand interference was low in monolinguals, more marked in bilinguals in Ll, and considerably higher in L2. On the basis of these findings the authors concluded that bilinguals revealed a lower degree of laterality for language and a greater righthemisphere participation in second language (L2) than in first language (Ll). Soares (1984) carried out a similar experiment (with a slightly different finger-tapping technique; see Green & Vaid, 1986) on 16 righthanded Portuguese-English male bilinguals, who had learned L2 after 12 years of age. He found a significantly greater degree of right-hand interference in monolinguals and bilinguals (both for Ll and L2). There were no lateralization differences across the bilinguals’ two languages or between bilinguals and monolinguals. Soares (1984) suggested that the differences between these results and those reported by Sussman et al. (1982) were due to the greater homogeneity in age and proficiency in Ll and L2 in his group of bilinguals. In addition, all the subjects in his group had learned L2 in an Anglo-Saxon environment, while this was true of only 70% of the bilinguals studied by Sussman et al. (1982), A. Green (1986) investigated cerebral lateralizations for Ll and L2 in four groups of male adults: (a) beginning Spanish learners, (b) low-intermediate Spanish learners, (c) fluent bilinguals, and (d) monolinguals. The first two groups showed a left-hemisphere dominance both for Ll and L2, whereas the fluent bilinguals (c) were significantly more bilateral in their first than in their second language. Green and Vaid (1986) as well
CEREBRAL LATERALIZATION
IN POLYGLOTS
75
as Simon and Sussman (1987) conducted an important debate on the best methods to adopt in tests with a verbal-manual interference paradigm. A number of questions regarding the correlation between the nervous system and polyglossia are still unanswered. We chose to inquire into some specific aspects, such as cerebral organization of language in an automatic speech production task in simultaneous interpreters who acquire a high proficiency in three languages (Ll: Italian; L2: English; and L3: German, French, Russian, or Spanish). Our study was also designed to investigate whether there are any cerebral specialization differences when interpreting simultaneously from L2 into Ll as compared to interpreting from Ll into L2 (Albert & Obler, 1978). In addition, it has been observed that interpreters develop different modes and strategies of interpreting according to type of discourse, fatigue conditions, etc. (Gran, 1988; Gran & Fabbro, 1988). Two paradigmatic modes of interpreting were chosen to study this specific aspect of simultaneous interpretation: the word-for-word (W-W) technique which is normally used for lists of nouns or figures, for highly technical subjects and under stress conditions, and the meaning-based (MB) strategy by which a different lexical and morphosyntactic form is used to reproduce the incoming message in the target language (TL). The latter mode of interpreting is used much more frequently, as the literal transposition of words from one language to the other would usually produce a distorted or meaningless outcome. Since this task, however, is more demanding, the two strategies are alternately adopted in simultaneous interpretation according to circumstances, personal characteristics, type of discourse, etc. The question of interest was whether these different modes of interpreting could involve different functional participation of the two cerebral hemispheres. In fact, studies on hemispheric specialization have shown that in right-handed subjects the left hemisphere is more involved in analytical and temporal tasks, while the right hemisphere functions in a synthetic, holistic, spatial manner (Trevarthen, 1984). The experimental hypotheses for this study were the following: 1. Hemispheric specialization differs according to direction of interpretation (L2 into Ll or Ll into L2); 2. Word-for-word interpretation involves greater left-hemisphere participation and, conversely, meaning-based interpretation requires increased right-hemisphere involvement. METHOD
Subjects Control group. The control group was composed of 14 female students in their third year at the Medical School, University of Trieste. All of them were right-handed as determined by the Briggs and Nebes (1975) test (HP: hand preference); ages ranged from 21 to 23 years, the mean age being 21.8 and none reported any family left-handedness.
76
FABBRO ET AL.
No subjects had hearing or neurological impairments. They were Italian monolinguals with a very limited knowledge of a second language (usually English) which they were not able to speak or understand in its spoken form. Experimenral group. Fourteen female fourth-year students from Scuola Superiore di Lingue Moderne per Interpreti e Traduttori (SSLM) of the University of Trieste formed the experimental group of subjects. All of them were right-handed as determined by the Briggs and Nebes (1975) test. Italian (Ll) was the mother tongue of all the subjects, and each had begun to learn L2 (English) after age 12. Most of them had learned L3 (German, French, Russian, or Spanish) in a classroom environment after age 18. Ages ranged from 22 to 26 years, the mean age being 24. Three subjects (see footnote, Table 2 and 3) reported family left handedness. No subject had hearing or neurological impairments. All the students had been trained in simultaneous interpretation from L2 to LI and vice versa for at least one year.
Procedure The verbal-manual interference paradigm developed by Kinsbourne and Cook (1971) and used by Sussman et al. (1982) was chosen to assess cerebral organization for language in bilinguals. In the experiment the subjects were instructed to press a button connected to a digital counter as fast as possible with their right index finger and then with their left index finger in silence for 20 sec. In theJirsf parf of the test the subjects of both groups (control and experimental group) performed eight control sessions of 20 set each of silent tapping with the right index finger (RH) and eight control sessions with the left index finger (LH). Each silent control tapping trial preceded an automatic language task, which consisted in reciting the days of the week, while tapping as fast as possible for 20 sec. Four 20-set sessions of reciting were performed during right-hand tapping and four during left-hand tapping in Ll by the students of the control group, and in Ll, L2, and L3 by the students of the experimental group. The average number of control taps in silence with each hand was computed for each subject and the average number of taps with each hand during the concurrent language task was determined for Ll, L2, and L3. The percentage of interference for each hand for the various languages was calculated using the following formula (see Sussman et al., 1982; Soares, 1984): % change = (No. taps control-No. taps concurrent) x loo No. taps control In the second part of the test the subjects of the experimental group performed eight sessions of silent tapping with each hand. The concurrent task consisted of four sessions of word-for-word (W-W) simultaneous interpreting from L2 (English) to Ll (Italian) and of four sessions of meaning-based (MB) simultaneous interpretation from L2 into Ll. The same modes and numbers of tasks were repeated from Ll into L2 during right- and lefthand tapping. Each subject performed a total of 16 sessions with each hand (four wordfor-word from L2 into Ll, four word-for-word from Ll into L2, four meaning-based from L2 into Ll, and four meaning-based from Ll into L2). Control and concurrent sessions were alternated and lasted 20 set each. The order of hand and direction of translation (L2 to LI and vice versa) was counterbalanced across subjects. The percentage of interference in simultaneous interpreting from L2 into Ll (and from Ll into L2) in the word-for-word and meaning-based modes was computed using the previously indicated formula. During the word-for-word simultaneous interpreting from L2 into Ll eight lists of common English words were administered; the same lists were used from LI into L2 in a different order. In each session of meaning-based interpreting from L2 into Ll three English sentences were administered, while three Italian sentences were used for each session of meaning-based simultaneous interpreting from Ll into L2. Proverbs and sentences were chosen for which there was no literal equivalent in the target language (TL); the subjects were thus obliged to change the lexicon and syntactic structure of the sentence in order
CEREBRAL LATERALIZATION
77
IN POLYGLOTS
to render its meaning in TL. The lists of words, proverbs and sentences in English and Italian are reported in the Appendix. The overall duration of the test was 2 hr for each subject; besides testing time, after every eight sessions the students were given a 5-min pause. Each subject was allowed a practice period at the tapping apparatus before the beginning of the experiment. The lists of words and sentences in Ll and L2 had been recorded by two adult female speakers, one of English and the other of Italian mother tongue, on a Revox B77MK2 4channel tape recorder. Each list of words and sentences in Ll and L2 lasted approximately 25 sec. The subjects heard the message with both ears and started to tap as fast as possible as soon as they heard the beginning of each sentence.
RESULTS
The change percentage scores in finger tapping were computed for each group and for each hand during: (a) automatic language tests in Ll for the control group, and in Ll, L2, and L3 for the experimental group; (b) the simultaneous interpreting task from L2 into Ll and vice versa in the word-for-word and in the meaning-based mode. Individual results are shown in Table 1, Table 2, and Table 3. A two-way analysis of variance for the first part of the experiment with the group of interpreting students (Ss x L x H; Ss: Subjects = 14; L: Language = 3; H: Hand = 2) showed a significant difference between languages in overall verbal-manual interference [right hand plus left hand, LI = 9.27%, L2 = 6.79%, L3 = 7.17%; F(2, 26) = 9.39, p < .OOl; see Fig. 1A]. The overall hand effect was not significant for the three languages [RH = 8.66%, LH = 6.83%; F( 1, 13) = 3.217, p = .09; see Fig. IB]. A two-way variance analysis (Ss x G x H; Ss: Subjects = 14; G: Group = 2; H: Hand = 2) conducted to investigate TABLE PERCENTAGE DISRUPTION
I SPEECH IN MONOLINGUAL
SUBJEUS
HP
RH
LH
21 21 22 22 22 23 22 22 21 22 22 21 23 22
f24 i24 f24 +24 +24 +24 +24 +20 +24 +24 +24 i24 +20 +24
9.0 9.3 12.2 9.8 6.6 6.6 5.9 0.9 6.6 7.3 6.3 15.8 3.0 8.8
6.1 9.1 8.6 8.8 7.0 7.0 10.0 1.2 8.1 4.8 5.6 11.5 5.2 8.5
21.8
+ 23.4
N
Age
I 2 3 4 5 6 7 8 9 10 11 12 13 14 Mean
IN AUTOMATIC
7.89
7.36
78
FABBRO
ET AL.
TABLE PERCENTAGE DISRUPTION
IN AUTOMATIC
2 SPEECH IN POLYGLOT INTERPRETERS
Ll
L2
L3
N
Age
HP
RH
LH
RH
LH
RH
LH
1 2 3* 4 5 6 7 8 9 10 11 12* 13 14*
25 26 22 24 25 22 24 24 25 23 24 22 26 26
+24 +24 +24 +24 +24 +24 +24 +24 +24 +24 +24 +24 +24 +22
10.3 12.6 7.2 9.4 9.8 8.1 8.4 4.7 6.9 4.7 13.7 14.2 15.1 8.6
5.0 11.5 11.8 9.7 7.0 8.6 8.6 9.1 2.5 8.6 16.5 13.6 3.1 10.2
6.8 7.6 13.4 6.8 9.3 6.5 11.3 5.4 1:8 3.7 16.4 11.2 8.2 5.7
8.4 2.4 7.6 4.9 2.2 4.8 I.1 4.4 3.3 8.2 7.8 14.5 -2.7 8.9
6.8 7.4 7.5 7.8 6.9 4.1 7.2 7.9 6.1 7.9 16.6 15.1 13.9 I.1
2.2 2.1 6.0 5.8 10.1 1.7 7.8 4.7 4.5 7.3 12.3 10.0 0.1 10.8
Mean
24
+23.8
* These subjects reported
9.55 family
8.99
8.15
5.42
8.30
6.10
left handedness.
TABLE PERCENTAGE DISRUCTION
3
IN SIMULTANEOUS
INTERPRETING
Ll into L2
L2 into Ll MB
W-W
w-w
MB
N
RH
LH
RH
LH
RH
LH
RH
LH
I 2 3* 4 5 6 7 8 9 IO II 12* 13 14*
9.0 -2.1 15.0 3.4 9.3 4.6 9.8 1.3 6.7 6.6 7.1 4.6 5.4 10.0
5.3 -3.0 6.9 6.9 12.6 11.0 1.2 5.9 6.9 7.5 15.4 15.3 - 1.1 11.1
13.6 13.2 20.2 11.6 11.5 9.2 15.1 10.1 6.6 3.0 10.9 12.1 6.5 7.8
11.6 5.3 9.1 12.6 18.1 13.7 5.2 7.0 15.3 7.6 19.5 12.6 5.2 8.1
3.4 4.5 11.5 10.4 10.5 5.7 9.5 3.2 10.1 6.1 7.0 14.1 5.8 9.2
-1.1 1.8 14.9 10.7 15.8 3.1 10.6 4.9 11.9 6.8 8.0 14.4 8.2 10.6
9.6 19.6 16.0 19.1 17.2 8.6 28.1 18.9 6.5 5.9 22.4 19.6 6.5 14.0
4.9 10.2 6.7 23.5 18.5 10.5 8.1 10.8 -2.5 6.6 13.2 19.5 15.9 11.2
10.81
10.77
Mean
6.47
7.27
* These subjects reported
family
left handedness.
7.92
8.61
15.14
11.22
CEREBRAL
LATERALIZATION
IN POLYGLOTS
A
Ll
Lz
79
B
L3
LH RH
FIG. 1. (A) Differences between languages (Ll, L2, L3) in overall verbal-manual interference in interpreting students (right hand plus left hand), p < .OOl. (B) Differences between right hand (RH) and left hand (LH) during automatic language tests in interpreting students, p = .0!9.
Italian language (Ll) lateralization in the two groups produced no significant difference in either [control group: right hand = 7.89%, left hand = 7.36%; interpreting group: right hand = 9.55%; left hand = 8.99%; hand factor F(1, 26) < 11. The group factor [F(l, 26) = 2.285, p < .ll and group-hand interaction [F( 1,26) < 11were not found to be significant. Two one-way variance analyses were conducted (Ss x H; Ss: Subjects = 14, H: Hand = 2) to establish cerebral lateralization for L2 and L3 in the group of interpreting students. No significant lateralization was found for the third language [L3: right hand = 8.30%; left hand = 6.10%; F(1, 13) = 2.492, p < .2], but a slight significance emerged for English [L2: right hand = 8.15%, left hand = 5.42%; F(1, 13) = 3.814, p = .07; see Fig. 21. For the second part of the experiment which only involved interpreting students, a three-way analysis of variance was performed (Ss x MI x DI x H; Ss: Subjects = 14, MI: Mode of Interpretation = 2, DI: Direction of Interpretation = 2, H: Hand = 2). There were no significant differences between the right and left hand [RH = 10.08%, LH = 9.47%; k’( 1, 13) < 1, see Fig. 3A]. Highly significant differences in verbal-manual interference were found with respect to the mode of simultaneous interpretation [word-for-word = 7.56%, meaning-based = 11.99%, F(1, 13) = 17.48, p < .OOl; see Fig. 3B] but not to the direction of interpretation [from L2 into Ll = 8.84%, from Ll into L2 = 10.72%, F(1, 13) = 3.151, p = .09; see Fig. 3C]. The interaction between mode of interpretation and direction of interpretation was not significant [word-for-
80
FABBRO ET AL. C.G.
-l
w RH
LH RI-I LH RH LH RH Ll
Lz
L3
FOG. 2. Verbal-manual interference of right hand (RH) and left hand (LH) for Ll (Italian) in control group (C.G.) and for Ll, L2 (English), p = .07, and L3 (German, French, Russian, or Spanish) in interpreting students U.S.).
0 11.99
10
i
6
g Q
6
4 2 0 LHRH
ww
ME
LzLl
LlLz
FIG. 3. (A) Differences between right hand (RH) and left hand (LH) during simultaneous interpretation. (B) Verbal-manual interference for mode of simultaneous interpretation (WW: word-for-word; MB: meaning-based); p < .OOl. (C) Verbal-manual interference for direction of simultaneous interpretation (L2Ll: from L2 into Ll; LlL2: from Ll into L2).
CEREBRAL
LATERALIZATION
IN POLYGLOTS
81
word L2 into Ll = 6.88%; word-for-word Ll into L2 = 8.26%; meaningbased L2 into Ll = 10.80%; meaning-based Ll into L2 = 13.18%; F( 1, 13) < 1; see Fig. 41. The mode of interpretation x hand interaction was significant [F(l, 13) = 4.83, p < .05]. A post hoc test (t-student) showed a significantly higher interference rate during meaning-based interpretation than during word-for-word interpretation both for the right and left hand. DISCUSSION
As outlined in the introduction, clinical data and some experimental neuropsychological tests have reported that right-handed bilinguals who have acquired a second language in adulthood are less lateralized for language functions than right-handed monolinguals (Albert & Obler, 1978; Vaid, 1983; Chary, 1986; Rogers et al., 1977; TenHouten, 1981; Scott et al., 1979; Vacate, 1984; Albanese, 1985; Fabbro et al., 1987a; Shanon, 1982; Sussman et al., 1982; A. Green, 1986). Other studies have reported marked left-hemisphere lateralization for both Ll and L2 (Galloway & Scarcella, 1982; Soares, 1984; Paradis, 1987; for a review see Vaid, 1983; Schneiderman, 1986). The present study considered motor specialization for Ll (Italian), L2 (English), and L3 (French, German, Spanish, or Russian) in a group of senior students at the School for Conference Interpreters (SSLM), University of Trieste, by using a verbal-manual interference paradigm. IJnlike Sussman et al. (1982), Soares (1984), and A. Green (1986) the ex-
WV L2Ll
WV
MB
MB
Ll L2
L2Ll
L112
FIG. 4. Verbal-manual interference for mode and direction of simultaneous interpretation (WWLZLl: word-for-word from L2 into Ll; WWLlL2: word-for-word from Ll into L2; MBL2Ll: meaning-based from L2 in*0 Ll; MBLIL2: meaning-based from Ll into L2).
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petted overall left-hemisphere dominance for Ll, L2, and L3 was not found. Percentage interference for Ll showed little difference between right and left hand, thus suggesting symmetrical cerebral organization in motor functions for Italian and the third language. The percentage disruption in finger tapping revealed a slightly higher interference for the right hand than for the left hand for L2. These findings suggest that in the group of students from the School for Interpreters there is greater overall verbal-motor interference for the Italian language as compared to L2 and L3. Interference is more symmetrical for Italian (Ll) and for the third language (L3) while there is slightly greater interference in righthand tapping for L2, indicating left-hemisphere motor dominance for this language. These results are at variance with those obtained by Sussman et al. (1982) and Soares (1984), but are somewhat similar to those obtained by A. Green (1986) with fluent bilinguals and by Fabbro (1990) in fingertapping experiments with right-handed fluent Friulian-Italian bilinguals and with non-right-handed polyglot students of translation and interpretation. Our impression is that in fluent female bilinguals the motor function representation of the first language in the two hemispheres is very probably more symmetrical than is the case with the second language. The female medical students (control group) are also less lateralized for language functions than the rest of right-handed persons. This may be the result of greater right-hemisphere involvement in the output control of the first language (it is well-known that fine intonation and accent are automatic/unconscious and are in all likelihood controlled by the right hemisphere; see Shapiro & Danly, 1985). The fact that both interpreters and medical students are females may be another explanation for the symmetrical representation of the first language (see Trevarthen, 1984). The greater interference in the first language compared to L2 and L3 might be attributed to the effect of practice, in that the subjects first performed the automatic language task in Ll, where order of hand and silent control trials was counterbalanced (Green & Vaid, 1986). This explanation seems insufficient, however, since the subjects had a practice session with both hands which was longer than the single language tapping sessions. Recent studies currently in publication (Fabbro, 1990) indicate that this effect may be linked to the type of automatic language chosen, i.e., with more complicated tasks, such as the reciting of prayers or proverbs, this effect is not manifested. The absence of first-language lateralization both in the group of interpreting students and in the control group suggests that right-handed women have, at least in Ll, a fairly symmetrical representation of language functions. On the other hand, L2 displayed a weak left-hemisphere lateralization, while L3 was not lateralized but displayed a tendency similar to L2. The different levels of proficiency in Ll, L2, and L3 may
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correspond to a different representation of these languages in the brain (Paradis, 1987; D. W. Green, 1986). In addition, an important factor may be the different levels of attention required by the performance of the various cognitive tasks (Tassinari, Fabbro, & Berlucchi, 1988). Numerous studies (Vaid, 1983, 1987; Paradis, 1987) including our investigation of dichotic listening with female interpreting students (Fabbro et al., 1987a) suggest left-hemisphere specialization of auditory decoding tasks in the mother tongue (Ll). Our study also showed symmetrical cerebral participation in motor functions for Ll (A. Green, 1986). For the second language (L2) auditory decoding processes appear to be symmetrically represented in the two hemispheres, while motor functions appear more left lateralized (Fabbro, Gran, Basso, & Bava, 1987b). In the second part of the experiment the aim was to study, for the first time, whether there are different hemispheric strategies for two paradigmatic modes of interpretation (word-for-word and meaning-based) in two different directions (L2 into Ll and Ll into L2). This experimental method did not show any differences in hemispheric dominance during simultaneous interpreting from Ll into L2 versus L2 into Ll, nor did the two modes of interpretation reveal any significant cerebral asymmetries in either direction (L2 into Ll and Ll into L2). The results obtained in the first part of the experiment gave grounds to expect greater right-hand interference in simultaneous interpretation from Ll to L2 since, in the automatic language tests, L2 showed weak left-hemisphere lateralization. This result was not observed, however, and neither were any other hemispheric specializations in the other types of simultaneous interpretation. These findings confirm the overall involvement of both hemispheres in simultaneous interpretation. An analysis of verbal-manual interference for modes of interpretation revealed highly significant differences between the word-for-word and the meaning-based mode. The disruption rate was higher for the meaningbased than for the word-for-word mode of interpretation both for the right and the left hand. A neurophysiological explanation for these results is not easily found. A higher degree of disruption in one task versus the other is probably due to a greater difficulty involved in that task. This phenomenon may be considered strictly from the point of view of motor functions (i.e., meaning-based interpretation involves motor structures of the nervous system more than does word-for-word interpretation), or from the point of view of cognitive or attentive strategies (Keefe, 1985). No greatly significant differences in hemispheric specialization for mode and direction of simultaneous interpretation were displayed. There are some possible explanations for this finding. Since both in the auditory decoding process and in the motor functions of language production, hemispheric lateralization differed between Ll and L2, the absence of significant lateralization in verbal-manual interference between each hand
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may be due to the concurrent activation of the two hemispheres in simultaneous interpreting. The experimental paradigm and procedures used in our study are insufficient to explain all the aspects involved in the complex and demanding task of simultaneous interpretation, and additional studies are necessary to analyze the complex neurophysiological organization of this brain process. It is possible, however, that simultaneous interpreters have a highly bilateral representation for language inasmuch as they are polyglots (see Albert & Obler, 1978; Vaid, 1983; Schneiderman, 1986; A. Green, 1986; Fabbro, 1990) and women, at least in an overwhelming majority of cases-93% of the interpreting student population at the School for Interpreters are girls (see Trevarthen, 1984). These factors may have such a strong influence on the cerebral organization for language that they radically modify normal language representation patterns as revealed by traditional studies on monolingual subjects. It is our intention to devote further experimental studies to specific aspects of simultaneous and consecutive interpreting in the near future. APPENDIX
List of Words bianco nero rosso Verde blu giallo rosa viola mart-one grigio dorato arancio scuro chiaro
= white = black = red = green = blue = yellow = pink = violet = brown = grey = golden = orange = dark = light
vecchio giovane nuovo nobile gentile crudele grass0 intelligente buono violent0 cattivo coraggioso stance noioso
= old = young = new = noble = kind = cruel =fat = intelligent = good = violent = bad = brave = tired = boring
facile pesante lung0 difticile alto soffice basso duro rumoroso prezioso assurdo secco caldo freddo
= easy = heavy = long = difficult = high = soft = low = hard = noisy = precious = absurd = dry = hot = cold
leggere scrivere parlare ascoltare studiare guardare capire vedere spiegare udire pensare imparare ricordare dimenticare
=to = to =to = to = to =to = to =to = to =to = to = to = to = to
read write speak listen study look understand see explain hear think learn remember forget
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APPENDIX-Continued ridere dormire ballare bere sognare amare lavare ringraziare pulire baciare piangere sorridere cantare
= to = to =to = to = to = to = to =to = to = to = to = to = to =to
laugh eat sleep dance drink dream love wash thank clean kiss cry smile sing
madre fratello cugino padre figlio sorella zia marito genitori moglie parenti amante figlia gemelli
= mother = brother = cousin =father = son = sister = aunt = husband = parents = wife = relatives = lover = daughter = twins
correre lavorare cavalcare pregare cucinare pagare viaggiare aiutare volare nuotare fumare mandare seguire Spagna Grecia Svezia Egitto Norvegia Giappone Polonia Giordania Ungheria Turchia Cipro Galles Olanda
English Proverbs and Phrases (I) To make a mountain out of a molehill. To be between the devil and the deep blue sea. He really does not know how to make both ends meet, Do not wash your dirty linen in public. (2) A bird in the hand is worth two in the bush. Every cloud has a silver lining. The wolf may lose his teeth, but never his nature. A word is enough to the wise. (3) Don’t have too many irons in the fire. That boy is as fit as a fiddle. The early bird catches the worm. You can’t have your cake and eat it. (4) The devil finds work for idle hands. It’s a bad workman who blames his tools. Mistakes are often the best teachers. It is easy to be wise after the event.
= to =to = to = to =to =to = to = to =to =to =to =to =to = to
run work ride pray cook walk pay travel help fly swim smoke send follow
= Greece = Sweden = Egypt = Denmark = Norway = Japan = Poland = Jordan = Hungary = Turkey = Cyprus = Wales =The Netherlands
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(5) You can’t run with the hare and hunt with the hounds. Fair and softly go far. An idle brain is the devil’s shop. Forewarned, forearmed. (6) If you run after two hares, you will catch neither. It takes all sorts to make a world. Little wit in the head makes much work for the feet. Cut your coat according to your cloth. (7) Clothes do not make the man. Desperate diseases have desperate cures. When in Rome do as the Romans do. Words are but wind, the written letter remains. (8) To kill two birds with one stone. You can lead a horse to water, but cannot make him drink. It takes two to make a quarrel. You can’t teach an old dog new tricks.
Italian Sentences (1) Quando qualcosa non funziona in quest0 ufficio, tutti tendon0 a fare a scaricabarili. In quest0 moment0 posso dire the le case sono a buon punto. La situazione era cosi difficile the non sapevo pih a the santo votarmi. (2) La faccenda non mi t chiara: vorrei sapere quell0 the belle in pentola. E’difficile seguire il suo discorso perche salta sempre di palo in frasca. Quando ascolti, devi fare attenzione a non prendere fischi per liaschi. (3) Prima di approvare quel progetto, dobbiamo andare con i piedi di piombo. Dopo aver gettato il denaro dalla finestra, e rimasta senza il becco di un quattrino. Quando vidi arrivare mia figlia, mi sembro di toccare il cielo con un dito. (4) Quando lesse la notizia sul giornale, rimase a bocca aperta. Quando si rese conto the le case non andavano bene, piantb baracca e burattini. Da quando Mary si i: sposata, la vedo una volta ogni morte di papa. (5) Non occorre the mi racconti quell0 the t successo, perch& lo so per lilo e per segno. Non si aspettava quella risposta e rimase con un palmo di naso. Quando gia si erano messi d’accordo, giunse Peter a rompere le uova nel paniere. (6) Ho l’impressione the egli si trovi con I’acqua alla gola a causa dei suoi debiti. Quando seppe the non era stato invitato, fete il diavolo a quattro. Non sa prendere alcuna iniziativa: aspetta sempre the gli piova la manna da1 cielo. (7) Maria e nata con la camicia: ha trovato un lavoro appena e arrivata qui. David it diventato un grande imprenditore perch& ha il bernoccolo degli affari. Mentre stavamo camminando insieme, John mi fete quella domanda di punto in bianco. (8) Quando Frank sta per partire e meglio non disturbarlo perch& ha un diavolo per capello. Oggigiorno i prezzi sono altissimi e diventa sempre piu difficile sbarcare il lunario. Quando le dissero the aveva vinto il premio, andb in un brodo di giuggiole.
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