Jutta L. Mueller

Learning a spoken language presupposes efficient auditory functions. In the present event-related potential study, we tested whether and how basic auditory processes are related to online learning of a linguistic rule in infants and adults. Participants listened to frequent standard stimuli, which were interspersed with infrequent pitch deviants and rule deviants, violating a nonadjacent dependency between two syllables. Only infants who showed the more mature mismatch response for the pitch deviants (i.e., a negativity) showed a mismatch response to the rule deviants. Concordantly, the small group of adults who showed evidence of rule learning showed larger mismatch effects for pitch processing. We conclude that the ability to extract linguistic rules develops in early infancy and is tightly linked to functional aspects of basic auditory mechanisms.

The ability to process center‐embedded structures has been claimed to represent a core function of the language faculty. Recently, several studies have investigated the learning of center‐embedded dependencies in artificial grammar settings. Yet some of the results seem to question the learnability of these structures in artificial grammar tasks. Here, we tested under which exposure conditions learning of center‐embedded structures in an artificial grammar is possible. We used naturally spoken syllable sequences and varied the presence of prosodic cues. The results suggest that mere distributional information does not suffice for successful learning. Prosodic cues marking the boundaries of the major relevant units, however, can lead to learning success. Thus, our data are consistent with the hypothesis that center‐embedded syntactic structures can be learned in artificial grammar tasks if language‐like acoustic cues are provided.

Artificial language studies have revealed the remarkable ability of humans to extract syntactic structures from a continuous sound stream by mere exposure. However, it remains unclear whether the processes acquired in such tasks are comparable to those applied during normal language processing. The present study compares the ERPs to auditory processing of simple Italian sentences in native and non-native speakers after brief exposure to Italian sentences of a similar structure. The sentences contained a non-adjacent dependency between an auxiliary and the morphologically marked suffix of the verb. Participants were presented four alternating learning and testing phases. During learning phases only correct sentences were presented while during testing phases 50 percent of the sentences contained a grammatical violation.

Previous research on event-related potentials (ERPs) on second language processing has revealed a great degree of plasticity in brain mechanisms of adult language learners. Studies with natural and artificial languages show that the N400 as well as the P600 component appear in learners after sufficient training. The present experiment tests if and which ERP components in response to syntactic and thematic processes generalize to unfamiliar lexical material in adult language learners. Learners of a miniature version of Japanese were presented with correct and incorrect sentences, half of which contained an unfamiliar word in the crucial sentence position. Incorrect sentences were either case-marking violations or word category violations. When all words were familiar, case-marking violations elicited a biphasic N400—P600 pattern and word category violations led to an early negativity that was followed by a P600. When the case violation occurred on an unfamiliar noun, only a P600 was seen. Word category violations that involved unknown verbs led to an early negativity and only to a reduced P600. The results suggest a high degree of nativelikeness for the learners during processing of familiar sentences. Unfamiliar words seem to entail additional processing costs and specifically lead to difficulties in the domain of case processing.

Humans can derive sequential dependencies from unfamiliar artificial speech within several of minutes of exposure. However, there is an ongoing debate about the nature of the underlying learning processes. In a widely discussed study Peña et al. [Peña, M., Bonatti, L. L., Nespor, M., & Mehler, J. Signal-driven computations in speech processing. Science, 298, 604–607, 2002] argued for the importance of subtle acoustic cues in the signal, such as pauses, in order to switch between two computational mechanisms, which are conceptualized as rule-based versus statistical. The present study was aimed to approach this problem by recording event-related potentials in response to correct and incorrect phrases consisting of bisyllabics after short exposure to either rule-based or random artificial speech streams. Rule-based streams contained dependencies of the form AXC, whereby A elements reliably predicted the C elements and X elements were variable. Participants were exposed to four input and test phases. Two of the input streams were rule-based and contained either only probabilistic information related to the distribution of the AXC stimuli or an additional acoustic cue indicating the boundaries of relevant units. The other two streams were random variations of the rule-based streams. During the test phase in the condition with pause cues, an early negativity and a later positivity emerged for correct and incorrect items in comparison to their acoustically identical counterparts, which were presented after the random control condition. In the noncued condition, only negativities were seen. The timing and the scalp distribution of the negativities were different for correct and incorrect sequences in both the cued and the noncued conditions. The results are interpreted in support of a view of grammatical learning in which both distributional and acoustic cues may contribute to different aspects of syntactic learning.

The present experiments were designed to test how the linguistic feature of case is processed in Japanese by native and non-native listeners. We used a miniature version of Japanese as a model to compare sentence comprehension mechanisms in native speakers and non-native learners who had received training until they had mastered the system. In the first experiment we auditorily presented native Japanese speakers with sentences containing incorrect double nominatives and incorrect double accusatives, and with correct sentences. In the second experiment we tested trained non-natives with the same material. Based on previous research in German we expected an N400-P600 biphasic ERP response with specific modulations depending on the violated case and whether the listeners were native or non-native.

The present chapter bridges two lines of neurocognitive research, which are, despite being related, usually discussed separately from each other. The two fields, second language (L2) sentence comprehension and artificial grammar processing, both depend on the successful learning of complex sequential structures. The comparison of the two research directions will be taken as the starting point for the attempt to study L2 sentence comprehension using a miniature language model. The experiments that will be presented made use of the event‐related potential (ERP) method, which provides a sensitive tool for the fast and multidimensional processes that characterize online processing of sequential structures.The first part of the article provides an overview of ERP studies on first and second language sentence comprehension and compares these to findings from the field of artificial grammar processing. In the second part, two studies in which native and nonnative sentence processing in the model of a miniature version of Japanese was investigated is presented. The findings of these studies suggest that miniature languages can serve as useful tools for capturing the impressive degree of plasticity as well as certain limitations in language comprehension mechanisms applied by learners.

Zusammenfassung Die Zusammenführung sprachwissenschaftlicher Theorien und neurophysiologischer Messverfahren führte in den letzten Jahrzehnten zu einem vertieften Verständnis der neuronalen Grundlagen der menschlichen Sprachverarbeitung. Spezifische in der Sprache enthaltene Informationstypen, wie z.B. grammatische Struktur oder Bedeutungsinformation, führen während des Sprachverstehens zu unterscheidbaren elektrophysiologischen und haemodynamischen Aktivierungen im Gehirn. In ersten Teil unseres Beitrags berichten wir über neuere Erkenntnisse der neurophysiologischen Sprachverarbeitungsforschung. Einen besonderen Einblick in die Plastizität des menschlichen Gehirns im Laufe seiner Entwicklung bietet die vergleichende Untersuchung von Sprachverarbeitungsprozessen in der Muttersprache und in später erlernten Fremdsprachen. Im zweiten Teil stellen wir die Ergebnisse neurophysiologischer Studien zur Sprachverarbeitung bei Nicht-Muttersprachlern vor und arbeiten die Bedeutung dieses Ansatzes zur Erforschung der neuronalen Grundlagen lebenslanger Lern- und Sprachverarbeitungsprozesse heraus.