The capacity for language is a defining property of our species, yet despite decades of research, evidence on its neural basis is still mixed and a generalized consensus is difficult to achieve. We suggest that this is partly caused by researchers defining “language” in different ways, with focus on a wide range of phenomena, properties, and levels of investigation. Accordingly, there is very little agreement among cognitive neuroscientists of language on the operationalization of fundamental concepts to be investigated in neuroscientific experiments. Here, we review chains of derivation in the cognitive neuroscience of language, focusing on how the hypothesis under consideration is defined by a combination of theoretical and methodological assumptions. We first attempt to disentangle the complex relationship between linguistics, psychology, and neuroscience in the field. Next, we focus on how conclusions that can be drawn from any experiment are inherently constrained by auxiliary assumptions, both theoretical and methodological, on which the validity of conclusions drawn rests. These issues are discussed in the context of classical experimental manipulations as well as study designs that employ novel approaches such as naturalistic stimuli and computational modeling. We conclude by proposing that a highly interdisciplinary field such as the cognitive neuroscience of language requires researchers to form explicit statements concerning the theoretical definitions, methodological choices, and other constraining factors involved in their work.

Complex human behavior is hierarchically organized. Whether or not syntax plays a role in this organization is currently under debate. The present ERP study uses piano performance to isolate syntactic operations in action planning and to demonstrate their priority over nonsyntactic levels of movement selection. Expert pianists were asked to execute chord progressions on a mute keyboard by copying the posture of a performing model hand shown in sequences of photos. We manipulated the final chord of each sequence in terms of Syntax (congruent/incongruent keys) and Manner (conventional/unconventional fingering), as well as the strength of its predictability by varying the length of the Context (five-chord/two-chord progressions). The production of syntactically incongruent compared to congruent chords showed a response delay that was larger in the long compared to the short context. This behavioral effect was accompanied by a centroparietal negativity in the long but not in the short context, suggesting that a syntax-based motor plan was prepared ahead. Conversely, the execution of the unconventional manner was not delayed as a function of Context and elicited an opposite electrophysiological pattern (a posterior positivity). The current data support the hypothesis that motor plans operate at the level of musical syntax and are incrementally translated to lower levels of movement selection.

Neuropsychological research investigating mental grammar and lexicon has largely been based on the processing of regular and irregular inflection. Past tense inflection of regular verbs is assumed to be generated by a syntactic rule (e.g., show-ed ), whereas irregular verbs consist of rather unsystematic alternations (e.g., caught ) represented as lexical entries. Recent morphological accounts, however, hold that irregular inflection is not entirely rule-free but relies on morphological principles. These subregularities are computed by the syntactic system. We tested this latter hypothesis by examining alternations of irregular German verbs as well as pseudowords using ERPs. Participants read series of irregular verb inflection including present tense, past participle, and past tense forms embedded in minimal syntactic contexts. The critical past tense form was correct (e.g., er sang [he sang]) or incorrect by being either partially consistent (e.g., * er sung [*he sung]) or inconsistent (e.g., * er sing [*he sing]) with the proposed morphological principles. Correspondingly, in a second experimental block, pseudowords (e.g., tang /* tung /* ting ) were presented. ERPs for real words revealed a biphasic ERP pattern consisting of a negativity and P600 for both incorrect forms in comparison to the correct equivalents. Most interestingly, the P600 amplitude for the incorrect forms was gradually modulated by the type of anomaly with medium amplitude for consistent past tense forms and largest amplitude for inconsistent past tense forms. ERPs for pseudoword past tense forms showed a similar gradual modulation of N400. The findings support the assumption that irregular verbs are processed by rule-based mechanisms because of subregularities of their past tense inflection.

Learning takes place throughout lifetime but differs in infants and adults because of the development of the PFC, a brain region responsible for cognitive control. To test this hypothesis, adults were investigated in a language learning paradigm under inhibitory, cathodal transcranial direct current stimulation over PFC. The experiment included a learning session interspersed with test phases and a test-only session. The stimulus material required the learning of grammatical dependencies between two elements in a novel language. In a parallel design, cathodal transcranial direct current stimulation over the left PFC, right PFC, or sham stimulation was applied during the learning session but not during the test-only session. Event-related brain potentials (ERPs) were recorded during both sessions. Whereas no ERP learning effects were observed during the learning session, different ERP learning effects as a function of prior stimulation type were found during the test-only session, although behavioral learning success was equal across conditions. With sham stimulation, the ERP learning effect was reflected in a centro-parietal N400-like negativity indicating lexical processes. Inhibitory stimulation over the left PFC, but not over the right PFC, led to a late positivity similar to that previously observed in prelinguistic infants indicating associative learning. The present data demonstrate that adults can learn with and without cognitive control using different learning mechanisms. In the presence of cognitive control, adult language learning is lexically guided, whereas it appears to be associative in nature when PFC control is downregulated.

There has been general consensus that initial word learning during early infancy is a slow and time-consuming process that requires very frequent exposure, whereas later in development, infants are able to quickly learn a novel word for a novel meaning. From the perspective of memory maturation, this shift in behavioral development might represent a shift from slow procedural to fast declarative memory formation. Alternatively, it might be caused by the maturation of specific brain structures within the declarative memory system that may support lexical mapping from the very first. Here, we used the neurophysiological method of ERPs to watch the brain activity of 6-month-old infants, when repeatedly presented with object–word pairs in a cross-modal learning paradigm. We report first evidence that infants as young as 6 months are able to associate objects and words after only very few exposures. A memory test 1 day later showed that infants did not fully forget this newly acquired knowledge, although the ERP effects indicated it to be less stable than immediately after encoding. The combined results suggest that already at 6 months the encoding process of word learning is based on fast declarative memory formation, but limitations in the consolidation of declarative memory diminish the long lasting effect in lexical-semantic memory at that age.

Although the neurocognitive processes underlying the comprehension of figurative language, especially metaphors and idioms, have been studied extensively, less is known about the processing of irony. In two experiments using event-related brain potentials (ERPs), we examined the types of cognitive processes involved in the comprehension of ironic and literal sentences and their relative time course. The experiments varied in modality (auditory, visual), task demands (comprehension task vs. passive reading), and probability of stimulus occurrence. ERPs consistently revealed a large late positivity (i.e., P600 component) in the absence of an N400 component for irony compared to equivalent literal sentences independent of modality. This P600 was shown to be unaffected by the factors task demands and probability of occurrence. Taken together, the findings suggest that the observed P600 is related to irony processing, and might be a reflection of pragmatic interpretation processes. During the comprehension of irony, no semantic integration difficulty arises (absence of N400), but late inferential processes appear to be necessary for understanding ironic meanings (presence of P600). This finding calls for a revision of current models of figurative language processing.

Recognition memory based on familiarity judgments is a form of declarative memory that has been repeatedly associated with the anterior medial temporal lobe. It has been argued that this region sustains familiarity-based recognition not only by retrieving item-specific information but also by coding for those semantic aspects of an event that support later familiarity-based recognition. Here, we used event-related fMRI to directly examine whether the contribution of anterior medial temporal lobe to declarative memory indeed results from its role in processing semantic aspects of an event. For this purpose, a sentence comprehension task was employed which varied the demands of semantic and syntactic processing of the sentence-final word. By presenting those sentence-final words together with new words in a subsequent incidental recognition memory test, we were able to determine the mnemonic consequences of presenting words in different sentential contexts. Results showed that enhanced semantic processing during comprehension activates regions in medial temporal lobe cortex and leads to response suppression in partly overlapping regions when the word is successfully retrieved. Data from a behavioral follow-up study support the view that enhanced semantic processing at study enhances familiarity-based remembering in a subsequent test phase.

In language learning, infants are faced with the challenge of decomposing continuous speech into relevant units, such as syntactic clauses and words. Within the framework of prosodic bootstrapping, behavioral studies suggest infants approach this segmentation problem by relying on prosodic information, especially on acoustically marked intonational phrase boundaries (IPBs). In the current ERP study, we investigate processing of IPBs in 5-month-old infants by varying the acoustic cues signaling the IPB. In an experiment in which pitch variation, vowel lengthening, and pause cues are present (Experiment 1), 5-month-old German infants show an ERP obligatory response. This obligatory response signals lower level perceptual processing of acoustic cues that, however, disappear when no pause cue is present (Experiment 2). This suggests that infants are sensitive to sentence internal pause, a cue that is relevant for the processing of IPBs. Given that German adults show both the obligatory components and the closure positive shift, a particular ERP component known to reflect the perception of IPBs, independent of the presence of a pause cue, the results of the current ERP study indicate clear developmental differences in intonational phrase processing. The comparison of our neurophysiological data from German-learning infants with behavioral data from English-learning infants furthermore suggests cross-linguistic differences in intonational phrase processing during infancy. These findings are discussed in the light of differences between the German and the English intonation systems.

Both language and music consist of sequences that are structured according to syntactic regularities. We used two specific event-related brain potential (ERP) components to investigate music-syntactic processing in children: the ERAN (early right anterior negativity) and the N5. The neural resources underlying these processes have been posited to overlap with those involved in the processing of linguistic syntax. Thus, we expected children with specific language impairment (SLI, which is characterized by deficient processing of linguistic syntax) to demonstrate difficulties with music-syntactic processing. Such difficulties were indeed observed in the neural correlates of music-syntactic processing: neither an ERAN nor an N5 was elicited in children with SLI, whereas both components were evoked in age-matched control children with typical language development. Moreover, the amplitudes of ERAN and N5 were correlated with subtests of a language development test. These data provide evidence for a strong interrelation between the language and the music processing system, thereby setting the ground for possible effects of musical training in SLI therapy.

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.

Verbal working memory, that is, the temporary maintenance of linguistic information in an activated state, is typically assumed to rely on phonological representations. Recent evidence from behavioral, neuropsychological, and electrophysiological studies, however, suggests that conceptual-semantic representations may also be maintained in an activated state. We developed a new semantic working memory task that involves the maintenance of a novel conceptual combination. Functional magnetic resonance imaging data acquired during the maintenance of conceptual combinations, relative to an item recognition task without the possibility of conceptual combination, demonstrate increased activation in the posterior left middle and inferior temporal gyri (known to be involved in conceptual representations) and left inferior frontal gyrus (known to be involved in semantic control processes). We suggest that this temporo-frontal system supports maintenance of conceptual information in working memory, with the frontal regions controlling the sustained activation of heteromodal conceptual representations in the inferior temporal cortex.

The functional neuroanatomy of language in the adult brain separates semantic and syntactic processes in the superior temporal gyrus (STG) and in the inferior frontal cortex. It is unknown whether a similar specialization is present in the developing brain. Semantic and syntactic aspects of sentence processing were investigated in 5- to 6-year-old children and in adults using functional magnetic resonance imaging. Although adults demonstrated function-specific activations in the STG and the frontal operculum, children showed a large activation overlap for these two language aspects in the STG. Compared to adults, they engaged additional areas in the left and right inferior frontal gyrus, which are known to support resource demanding processes. Thus, the language networks for semantic and syntactic processes are not yet specialized similarly to adults in the developing brain.

The interaction between language and action systems has become an increasingly interesting topic of discussion in cognitive neuroscience. Several recent studies have shown that processing of action verbs elicits activation in the cerebral motor system in a somatotopic manner. The current study extends these findings to show that the brain responses for processing of verbs with specific motor meanings differ not only from that of other motor verbs, but, crucially, that the comprehension of verbs with motor meanings (i.e., greifen , to grasp) differs fundamentally from the processing of verbs with abstract meanings (i.e., denken , to think). Second, the current study investigated the neural correlates of processing morphologically complex verbs with abstract meanings built on stems with motor versus abstract meanings (i.e., begreifen , to comprehend vs. bedenken , to consider). Although residual effects of motor stem meaning might have been expected, we see no evidence for this in our data. Processing of morphologically complex verbs built on motor stems showed no differences in involvement of the motor system when compared with processing complex verbs with abstract stems. Complex verbs built on motor stems did show increased activation compared with complex verbs built on abstract stems in the right posterior temporal cortex. This result is discussed in light of the involvement of the right temporal cortex in comprehension of metaphoric or figurative language.

The present study investigated the automaticity of morphosyntactic processes and processes of syntactic structure building using event-related brain potentials. Two experiments were conducted, which contrasted the impact of local subject-verb agreement violations (Experiment 1) and word category violations (Experiment 2) on the mismatch negativity, an early event-related brain potential component reflecting automatic auditory change detection. The two violation types were realized in two-word utterances comparable with regard to acoustic parameters and structural complexity. The grammaticality of the utterances modulated the mismatch negativity response in both experiments, suggesting that both types of syntactic violations were detected automatically within 200 msec after the violation point. However, the topographical distribution of the grammaticality effect varied as a function of violation type, which indicates that the brain mechanisms underlying the processing of subject-verb agreement and word category information may be functionally distinct even at this earliest stage of syntactic analysis. The findings are discussed against the background of studies investigating syntax processing beyond the level of two-word utterances.

The present study investigated the processing of two types of artificial grammars by means of event-related brain potentials. Two categories of meaningless CV syllables were applied in each grammar type. The two grammars differed with regard to the type of the underlying rule. The finite-state grammar (FSG) followed the rule (AB) n , thereby generating local transitions between As and Bs (e.g., n = 2, ABAB). The phrase structure grammar (PSG) followed the rule A n B n , thereby generating center-embedded structures in which the first A and the last B embed the middle elements (e.g., n = 2, [A[AB]B]). Two sequence lengths ( n = 2, n = 4) were used. Violations of the structures were introduced at different positions of the syllable sequences. Early violations were situated at the beginning of a sequence, and late violations were placed at the end of a sequence. A posteriorly distributed early negativity elicited by violations was present only in FSG. This effect was interpreted as the possible reflection of a violated local expectancy. Moreover, both grammar-type violations elicited a late positivity. This positivity varied as a function of the violation position in PSG, but not in FSG. These findings suggest that the late positivity could reflect difficulty of integration in PSG sequences.

The present study investigated the role of proficiency in late second-language (L2) processing using comparable stimuli in German and Italian. Both sets of stimuli consisted of simple active sentences including a word category violation, a morphosyntactic agreement violation, or a combination of the two. Four experiments were conducted to study high- and low-proficiency L2 learners of German as well as high- and low-proficiency L2 learners of Italian. High-proficiency L2 learners in both languages showed the same event-related potential (ERP) components as native speakers for all syntactic violations. For the word category violation, they displayed an early anterior negativity (ELAN), an additional negativity reflecting reference-related processes, and a late P600 evidencing processes of reanalysis. For the processing of the morphosyntactic error, an anterior negativity (LAN) and a P600 were observed, whereas for the combined violation, the same ERP components were found as in the pure category violation. In high-proficiency L2 learners, the timing of the processing steps was equivalent to that of native speakers, although some amplitude differences were present. Low-proficiency L2 learners, however, showed qualitative differences in the agreement violation characterized by the absence of the LAN and quantitative differences reflected in a delayed P600 in every violation condition. These findings emphasize that with a high proficiency, late L2 learners can indeed show native-like neural responses with the timing approximating that of native speakers. This challenges the idea that there are fundamental differences in language processing in the brain between natives and late L2 learners.

Psycholinguistic theories assume an interaction between prosody and syntax during language processing. Based on studies using mostly off-line methods, it is unclear whether an interaction occurs at later or initial processing stages. Using event-related potentials, the present study provides neurophysiological evidence for a prosody and syntax interaction in initial processing. The sentence material contained mere prosodic and syntactic as well as combined prosodic-syntactic violations. For the syntax violation, the critical word appeared after a preposition. The suffix of the critical word either indicated a noun fulfilling the syntactic requirements of the preceding preposition or a verb causing a word category violation. For the prosodic manipulation, congruent critical words were normally intonated (signaling sentence continuation) while prosodically incongruent critical words signaled sentence end. For the mere prosodic incongruity, a broadly distributed negativity was observed at the critical word-stem (300–500 msec aligned to word onset). In response to a mere syntactic error, a left temporal negativity was elicited in an early time window (200–400 msec aligned to suffix onset), taken to reflect initial phrase structure building processes. In contrast, in response to the combined prosodic-syntactic violation, an early temporal negativity showed up bilaterally at the suffix in the same time window. Our interpretation is that the process of initial structure building as reflected in the early left anterior negativity recruits additional right hemispheric neural resources when the critical word contains both syntactic and prosodic violations. This suggests the immediate influence of phrasal prosody during the initial parsing stage in speech processing.

A neural correlate for phrase boundary perception in music has recently been identified in musicians. It is called music closure positive shift (“music CPS”) and has an equivalent in the perception of speech (“language CPS”). The aim of the present study was to investigate the influence of musical expertise and different phrase boundary markers on the music CPS, using event-related brain potentials (ERPs) and event-related magnetic fields (ERFs). Musicians and nonmusicians were tested while listening to binary phrased melodies. ERPs and ERFs of both subject groups differed considerably from each other. Phrased melody versions evoked an electric CPS and a magnetic CPSm in musicians, but an early negativity and a less pronounced CPSm in nonmusicians, suggesting different perceptual strategies for both subject groups. Musicians seem to process musical phrases in a structured manner similar to language. Nonmusicians, in contrast, are thought to detect primarily discontinuity in the melodic input. Variations of acoustic cues in the vicinity of the phrase boundary reveal that the CPS is influenced by a number of parameters that are considered to indicate phrasing in melodies: pause length, length of the last tone preceding the pause, and harmonic function of this last tone. This is taken as evidence that the CPS mainly reflects higher cognitive processing of phrasing, rather than mere perception of pauses. Furthermore, results suggest that the ERP and MEG methods are sensitive to different aspects within phrase perception. For both subject groups, qualitatively different ERP components (CPS and early negativity) seem to reflect a top-down activation of general but different phrasing schemata, whereas quantitatively differing MEG signals appear to reflect gradual differences in the bottom-up processing of acoustic boundary markers.

During their first year of life, infants not only acquire probabilistic knowledge about the phonetic, prosodic, and phonotactic organization of their native language, but also begin to establish first lexical-semantic representations. The present study investigated the sensitivity to phonotactic regularities and its impact on semantic processing in 1-year-olds. We applied the method of event-related brain potentials to 12-and 19-month-old children and to an adult control group. While looking at pictures of known objects, subjects listened to spoken nonsense words that were phonotactically legal ( pseudowords ) or had phonotactically illegal word onsets ( nonwords ), or to real words that were either congruous or incongruous to the picture contents. In 19-month-olds and in adults, incongruous words and pseudowords, but not non-words, elicited an N400 known to reflect mechanisms of semantic integration. For congruous words, the N400 was attenuated by semantic priming. In contrast, 12-month-olds did not show an N400 difference, neither between pseudo-and nonwords nor between incongruous and congruous words. Both 1-year-old groups and adults additionally displayed a lexical priming effect for congruous words, that is, a negativity starting around 100 msec after words onset. One-year-olds, moreover, displayed a phonotactic familiarity effect, that is, a widely distributed negativity starting around 250 msec in 19-month-olds but occurring later in 12-month-olds. The results imply that both lexical priming and phonotactic familiarity already affect the processing of acoustic stimuli in children at 12 months of age. In 19-month-olds, adult-like mechanisms of semantic integration are present in response to phonotactically legal, but not to phonotactically illegal, nonsense words, indicating that children at this age treat pseudo-words, but not nonwords, as potential word candidates.

Event-related brain potential (ERP) studies of sentence processing in adults have shown that phrase-structure violations are associated with two ERP components: an early left anterior negativity (ELAN) and a late, centro-parietal positivity (P600). Although the ELAN reflects highly automatic first-pass sentence parsing, the P600 has been interpreted to reflect later, more controlled processes. The present ERP study investigates the processing of phrase-structure violations in children below three years of age. Both children (mean age of 2.8 years) and adults passively listened to short active sentences that were either correct or syntactically incorrect. Adults displayed an ELAN that was followed by a P600 to the syntactic violation. Children also demonstrated a biphasic ERP pattern consisting of an early left hemispheric negativity and a late positivity. Both components, however, started later and persisted longer than those observed in adults. The left lateralization of the children's negativity suggests that this component can be interpreted as a child-specific precursor to the ELAN observed in adults. The appearance of the early negativity indicates that the neural mechanisms of syntactic parsing are present, in principle, during early language development.