Perceived foreign accent in first language attrition and second language acquisition: The impact of age of acquisition and bilingualism

This study investigates constraints on ultimate attainment in second language (L2) pronunciation in a direct comparison of perceived foreign accent of 40 late L2 learners and 40 late first language (L1) attriters of German. Both groups were compared with 20 predominantly monolingual controls. Contrasting participants who acquired the target language from birth (monolinguals, L1 attriters) with late L2 learners, on the one hand, and bilinguals (L1 attriters, L2ers) with monolinguals, on the other hand, allowed us to disentangle the impacts of age of onset and bilingualism in speech production. At the group level, the attriters performed indistinguishably from controls, and both differed from the L2 group. However, 80% of all L2ers scored within the native (attriter) range. Correlational analyses with background factors further found some effects of use and language aptitude. These results show that acquiring a language from birth is not sufficient to guarantee nativelike pronunciation, and late acquisition does not necessarily prevent it. The results are discussed in the light of models on the role of age and cross-linguistic influence in L2 acquisition. Studies on age effects in second language (L2) acquisition show that pronunciation accuracy in the target language is one of the most difficult skills to acquire for late learners. Such investigations consistently demonstrate that postpuberty learners across different acquisition contexts are detectably different in speech production from monolingual native speakers and from early L2 learners (L2ers). The most robust finding is that foreign accent ratings show a negative correlation with age of acquisition (AOA); that is, the later an L2er is exposed to the L2, the stronger the foreign accent tends to be at the endstate of the acquisition process © Cambridge University Press 2011 0142-7164/11 $15.00 terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0142716411000737 Downloaded from https:/www.cambridge.org/core. IP address: 54.202.195.117, on 12 Apr 2017 at 21:44:36, subject to the Cambridge Core Applied Psycholinguistics 34:2 362 Hopp & Schmid: Perceived foreign accent in L1 attrition and L2 acquisition (e.g., Abrahamsson & Hyltenstam, 2009; Flege et al., 2006). As a consequence, AOA has been taken to be the primary predictor for pronunciation accuracy at L2 ultimate attainment. However, previous research also suggests that the link may not be entirely straightforward. In particular, researchers differ in how they conceptualize age effects in L2 speech production, the crucial question being whether AOA is the cause of persisting transfer from the first language (L1) or whether it is merely associated with it (Bialystok, 1997, 2001). Some researchers interpret age effects as a direct reflection of a “critical” or “sensitive” period in the L2 acquisition of articulatory phonology and phonetics, which preempts nativelike pronunciation in late learners. In this view, behavioral deviance in L2 production compared to native speech has been linked to constraints in neurological and fine motor skills (e.g., Moyer, 1999). These constraints are argued to follow from maturational reductions in cerebral plasticity, which categorically prevent the reorganization of the speech production (and comprehension) system from the L1 to the L2 after a certain age (e.g., DeKeyser & Larson-Hall, 2005; Hyltenstam & Abrahamsson, 2003). The location of this cutoff age for attaining nativelikeness is controversial, ranging from shortly after birth (Abrahamsson & Hyltenstam, 2009; Hyltenstam & Abrahamsson, 2003) through age 6 (Long, 1990) to puberty (DeKeyser, 2000; Scovel, 1988). Others have interpreted age-related increments in foreign accent to be a consequence of the degree of L1 entrenchment in phonetic categorization, rather than maturational constraints on speech production. For instance, the speech learning model (Flege, 2002) hypothesizes that L2 learners are increasingly likely to process L2 phonetic categories as instances of L1 categories the longer the L1 had been spoken before the onset of L2 acquisition (Flege, 1999). On this view, even though differences between L1 and L2 vowel and consonant categories may be detectable in comprehension, the classification of L2 phones as functional equivalents of L1 categories leads to the merging of L1 and L2 categories in speech production. The entrenchment model implies that factors other than just AOA may impact on (non)native L2 pronunciation. Previous research has considered a wide variety of predictors such as length of residence in an L2 environment (LOR), chronological age at testing, typological distance of the languages, language use, language aptitude, and sociopsychological factors (for an overview, see Jesney, 2004). As has often been noted, however, many of these factors are confounded or covary with AOA. LOR, for example, is of necessity longer for earlier learners if they are age-matched to late learners at time of testing (e.g., Flege, 2009; Moyer, 2007; Piske, MacKay, & Flege, 2001). In a similar vein, language use is linked with AOA because early L2ers who arrive in the target-language environment before age 10 tend to adopt the L2 as the main language of communication, whereas late L2ers retain higher degrees of use of the L1 in the target-language environment as well as in contacts to their home community (e.g., Jia, Aaronson & Wu, 2002; Piske et al., 2001). In addition, such investigations face the methodological problem that use of the L1/21 can only be measured on the basis of self-reports, which may not always be reliable. These problems may account to some extent for multifactorial analyses of L2 speech production often yielding mixed results, with factors other than AOA terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0142716411000737 Downloaded from https:/www.cambridge.org/core. IP address: 54.202.195.117, on 12 Apr 2017 at 21:44:36, subject to the Cambridge Core Applied Psycholinguistics 34:2 363 Hopp & Schmid: Perceived foreign accent in L1 attrition and L2 acquisition accounting only for a small amount of variance. For instance, in a meta-analysis of data from 240 L1 Korean and 240 L1 Italian L2ers of English across several tasks and studies, Flege (2009) reports that amount of L1/2 use accounts for less than 10% of the variance in foreign accent rating data. It hence remains to be investigated how factors such as use can be reliably assessed and how they affect L2 pronunciation independently of AOA. The controversy on the role of the age effect in SLA is further complicated by findings suggesting that even L2 speakers with AOAs well below the onset of puberty do not invariably score within the native range (e.g., MacKay, Flege, & Imai, 2006; Piske et al., 2001). For instance, Korean children who arrived in the United States between the ages of 8 and 9 and who were tested after 3 and 5 years of residence were reliably rated as having a foreign accent compared to age-matched native English children (Flege et al., 2006; see also Flege, Munro, & MacKay, 1995; Flege, Yeni-Komshian, & Liu, 1999). Similar effects are reported for Italian learners of English by MacKay et al. (2006). In contrast, Pallier et al. (2003), Ventureyra (2005), and Ventureyra, Pallier, and Yoo (2004) suggest that speakers who experience sequential monolingualism, that is, a complete break in L1 input followed by a rapid breakdown of this system and full immersion in another language in all contexts of life (as experienced by international adoptees) may become fully nativelike in L2 speech perception even if this language reversal took place as late as age 10 (but see Hyltenstam, Bylund, Abrahamsson, & Park, 2009). Given the apparently relatively minor contribution of predictors other than age (such as L1/2 use) as well as the fact that even early learners may be perceptibly different from monolingual natives unless a complete language reversal has taken place, one may hypothesize that being a bilingual speaker in and of itself contributes to perceived nonnativeness. It has long been acknowledged that the end state in bilingual development cannot be equated with dual monolingualism (Grosjean, 1998). Rather, it has been argued that multicompetence in more than one language should be taken to be the ultimate goal of L2 acquisition (Cook, 2003). In other words, a proficient bilingual inherently differs from a monolingual by virtue of accessing an integrated language processing system that is partly shared across languages. This in turn implies interactions and cross-linguistic influence across both (or all) languages at multiple cognitive and linguistic levels that monolinguals do not experience. Cross-linguistic interactive effects in bilinguals have been well documented in cognitive processing (e.g., Bialystok, 2009) and linguistic processing at different levels (e.g., van Hell & Dijkstra, 2002, for the bilingual mental lexicon; Hernandez, Bates, & Avila, 1994, for sentence processing; Cutler, Mehler, Norris, & Segui, 1989, for the structuring of phonetic space). Bilingualism affects strategies and mechanisms of L1 and L2 processing (e.g., Dussias, 2004), as well as the speed of processing in either language (e.g., Hopp, 2010; McDonald, 2000), even if both languages are acquired from early childhood (Foursha, Austin, & van de Walle, 2005; Proverbio, Cok, & Zani, 2002; Werker & Byers-Heinlein, 2008). For pronunciation, several studies report bidirectional cross-linguistic influence in the speech production of bilinguals. Flege (1987; see also Flege & Hillenbrand, 1984) studied late English–French and French–English bilinguals of different terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0142716411000737 Downloaded from https:/www.cambridge.org/core. IP address: 54.202.195.117, on 12 Apr 2017 at 21:44:36, subject to the Cambridge Core Applied Psycholinguistics 34:2 364 Hopp & Schmid: Perceived foreign accent in L1 attrition and L2 acquisition proficiency levels after some period of residence in an L2 environment. A comparison with monolingual controls of either language revealed that voice onset time (VOT) produced by the bilinguals in both their languages diverged from the monolingual norm (i.e., all bilingual speakers had shorter VOTs in English and longer VOTs in French than the controls). The degree of bidirectional influence was modulated by proficiency levels and length of residence in the L2 environment. In a similar vein, Fowler, Sramko, Ostry, Rowland, and Hallé (2008) report that simultaneous (2L1) French–English speakers produce VOTs in either language that are different from those produced by monolingual native speakers (Fowler et al., 2008).2 Although the bilinguals’ VOTs clearly differ between English and French, indicating that phones do not merge across languages, the realization of those phones in one language affects their realization in the other. These effects point to assimilatory processes in speech production (see also Sancier & Fowler, 1997) and perception (e.g., Sundaraa, Polkaa, & Genesee, 2006). Such cross-linguistic interaction seems to result from the active use of two languages, since the monolingual controls in the Fowler et al. study did not differ in their VOTs depending on whether they were occasionally exposed to the other language or not (but see Au, Knightly, Jun, & Oh, 2002; Caramazza, Yeni-Komshian, Zurif, & Carbone, 1973). Despite these widely recognized cross-linguistic interactions that affect speech production and comprehension in bilinguals across AOAs, the reference groups in speech production studies typically consist of monolingual native speakers of the target language (e.g., Flege et al., 2006) or native speakers who overwhelmingly use the target language but might have some knowledge of other languages (e.g., Abrahamsson & Hyltenstam, 2009). It may be argued that the choice of a monolingual control group thus moves the yardstick of nativelikeness to a point that may, by definition, be out of reach for most bilinguals (see also Birdsong, 2005). It may therefore be more appropriate to investigate whether L2ers can approximate the performance of speakers who have acquired the target language from birth but are also advanced late learners of an L2. In this respect, 2L1 speakers, that is, bilinguals from birth, are unsuitable as a reference point in a direct comparison with late L2 learners because they differ in their chronological onset of bilingualism. In 2L1 speakers, assimilatory tendencies in phonetic categories across languages can be observed from the beginning of language acquisition due to concurrent L1 and L2 input (Fowler et al., 2008). In other words, 2L1 speakers arguably never develop monolingual native categories, which can then be affected by the later onset of bilingualism. In this way, they fundamentally differ from late L2 learners whose native (monolingual) phonetic categories affect speech production of a late-acquired language, and vice versa. Similarly, early (child) L2ers, who are typically compared with late learners in studies on age effects in L2 acquisition, differ in their degree of entrenchment of L1 phonetic categories. Given the comparatively shorter length of exclusive L1 use for child L2ers, the impact of the L1 on a successively acquired L2 may be quantitatively distinct from the extent of cross-linguistic influence experienced by late learners (Flege et al., 2006). The present study therefore introduces a bilingual reference group who shares the chronological asymmetry in the onset of L1 and L2 input characteristic of terms of use, available at https:/www.cambridge.org/core/terms. https://doi.org/10.1017/S0142716411000737 Downloaded from https:/www.cambridge.org/core. IP address: 54.202.195.117, on 12 Apr 2017 at 21:44:36, subject to the Cambridge Core Applied Psycholinguistics 34:2 365 Hopp & Schmid: Perceived foreign accent in L1 attrition and L2 acquisition late L2 acquisition: L1 attriters, that is, adult long-term emigrants to a nontarget language environment whose use of their early-acquired L1 is greatly reduced following emigration. Both these bilingual populations are then compared against a (largely) monolingual reference group.