Statistical Learning of a Morse Code Language is Improved by Bilingualism and Inhibitory Ability

Statistical Learning of a Morse Code Language is Improved by Bilingualism and Inhibitory Ability James Bartolotti, Viorica Marian, Scott R. Schroeder, Anthony Shook Department of Communication Sciences and Disorders, 2240 Campus Drive Evanston, IL 60208 USA Abstract semantic level. Increased flexibility in either of these processes would allow for accelerated vocabulary acquisition in bilinguals, leading to rapid gains in novel language knowledge. Vocabulary learning is particularly important in attaining language fluency; by some estimates learners need to know 98% of the words they hear to comprehend speech which translates to roughly 8000 lexical items (Nation, 2006). The size of vocabularies means that many words are acquired incidentally, either by reading or listening to speech (Schmitt, 2008). Words acquired from speech are notoriously difficult to learn, in part because the boundaries between words are not always obvious. One way to overcome the word boundary problem is to attend to the regularities in speech. Sounds that co-occur often are likely to comprise part of a single word, whereas rare sound sequences are likely to mark transitions between words. These transitions can mark the beginning of novel words, which should be attended to and encoded by the learner. Infants demonstrate attention to statistical probabilities in a continuous auditory sequence (Saffran, Aslin, & Newport, 1996), as do adults (Saffran, Johnson, Aslin, & Newport, 1999), and this skill has been associated with word-learning ability (Mirman, Magnuson, Estes, & Dixon, 2008). It is a flexible process that can be applied to successfully learn words composed of speech phonemes, musical tones, or visual sequences (Saffran, et al., 1999; Slemmer, Kirkham, & Johnson, 2010), and may reflect the process by which language learners acquire words from spoken speech. A potential difficulty during novel language acquisition remains, though, in that the novel language is prone to interference from already known languages. Interaction between languages is observed during language processing and can lead to interference (Bijeljac-Babic, Biardeau, & Grainger, 1997; Blumenfeld & Marian, 2007; Duyck, Assche, Drieghe, & Hartsuiker, 2007; Marian & Spivey, 2003a; 2003b; Schwartz & Kroll, 2006; van Heuven, Dijkstra, & Grainger, 1998). In the process of acquiring a new language, interference from known languages may be particularly destructive, as known languages are highly practiced and may activate more easily. Better suppression of non-target language activation may consequently improve attention to novel language cues and facilitate acquisition. Inhibitory control ability is one way to manage this interference, by reducing activation of irrelevant items. Strong inhibitory control has been associated with improved statistical learning in situations where interference during learning was particularly pronounced (Weiss, Gerfen, & Mitchel, 2010). Bilinguals display advantages in inhibitory We examine the influence of bilingualism and inhibitory control on the ability to learn a novel language. Using a statistical learning paradigm, participants learned transitional probabilities in two novel languages based on the International Morse Code. First, participants listened to a low- interference language to test word segmentation skill. Next, participants listened to a high-interference language, in which a colliding cue to word boundaries in the form of compressed pauses between words conflicted with the language’s transitional probabilities. Results suggest that high proficiency in a second language can improve word learning in a novel language, but when interference during learning is high, language experience no longer confers a benefit and strong inhibitory control ability is necessary for learning to occur. Keywords: recognition language acquisition; bilingualism; pattern Introduction Language learning is a complex phenomenon that requires the learner to incorporate novel phonology, vocabulary, and grammatical rules. Not surprisingly, acquiring a new language can be difficult, particularly later in life, and many learners never achieve full native-like proficiency (Birdsong, 2006; 2009; DeKeyser, 2005). Learning outcomes may be improved by identifying the processes that contribute to successful acquisition of a novel language. One of the first steps to language acquisition is to understand the way in which sounds are combined to create words. After identifying novel sound sequences, they can be assigned to semantic concepts and the complete word added to one’s vocabulary. Here we consider how two related factors, bilingual language experience and inhibitory control, may influence this word acquisition process. Bilingualism has been shown to provide a language learning advantage, and bilinguals acquiring a third language outperform monolinguals acquiring a second language (Cenoz & Valencia, 1994; Kaushanskaya & Marian, 2009a; 2009b; Keshavarz & Astaneh, 2004; Sanz, 2000; Thomas, 1992). This may be due in part to bilinguals’ enhanced working memory, which allows them to sustain novel words in the focus of attention until they can be encoded in long-term memory (Papagno & Vallar, 1995; van Hell & Mahn, 1997), and is linked to high second- language proficiency (Majerus, Poncelet, van der Linden, & Weekes, 2008; Service, Simola, Metsanheimo, & Maury, 2002). These novel words may be more readily linked to novel sound sequences at the phonological level, or mapped onto concepts shared with translation equivalents at the