Phonotactic knowledge of word boundaries and its use in infant speech perception

The development of a lexicon critically depends on the infant’s ability to identify wordlike units in the auditory speech input. The present study investigated at what age infants become sensitive to language-specific phonotactic features that signal word boundaries and to what extent they are able to use this knowledgeto segment speech input. Experiment 1 showed that infants at the age of 9 months were sensitive to the phonotactic structure of word boundaries when wordlike units were presented in isolation. Experiments 2 to 5 demonstrated that this sensitivity was present even when critical items were presented in context, although only under certain conditions. Preferences for legal over illegal word boundary clusters were found when critical items were embedded in two identical syllables, keeping language processing requirements and attentional requirements low. Experiment 6 replicated the findings of Experiment 1. Experiment 7 was a low-pass-filtered version of Experiment 6 that left the prosody of the stimulus items intact while removing most of the distinctive phonotactic cues. As expected, no listening preference for legal over illegal word boundary clusters was found in this experiment. This clearly suggests that the preferential patterns observed can be attributed to the infants’ sensitivity to phonotactic constraints on word boundaries in a given language and not to suprasegmental cues.     

Listeners learn phonotactic patterns conditioned on suprasegmental cues

Language learners are sensitive to phonotactic patterns from an early age, and can acquire both simple and 2nd-order positional restrictions contingent on segment identity (e.g., /f/ is an onset with /æ/but a coda with /?/). The present study explored the learning of phonototactic patterns conditioned on a suprasegmental cue: lexical stress. Adults first heard non-words in which trochaic and iambic items had different consonant restrictions. In Experiment 1, participants trained with phonotactic patterns involving natural classes of consonants later falsely recognized novel items that were consistent with the training patterns (legal items), demonstrating that they had learned the stress-conditioned phonotactic patterns. However, this was only true for iambic items. In Experiment 2, participants completed a forced-choice test between novel legal and novel illegal items and were again successful only for the iambic items. Experiment 3 demonstrated learning for trochaic items when they were presented alone. Finally, in Experiment 4, in which the training phase was lengthened, participants successfully learned both sets of phonotactic patterns. These experiments provide evidence that learners consider more global phonological properties in the computation of phonotactic patterns, and that learners can acquire multiple sets of patterns simultaneously, even contradictory ones.     

Structural constraints in the perception of English stop-sonorant clusters

Native-language phonemes combined in a non-native way can be misperceived so as to conform to native phonotactics, e.g. English listeners are biased to hear syllable-initial [tr] rather than the illegal [tl] (Perception and Psychophysics 34 (1983) 338; Perception and Psychophysics 60 (1998) 941). What sort of linguistic knowledge causes phonotactic perceptual bias? Two classes of models were compared: unit models, which attribute bias to the listener's differing experience of each cluster (such as their different frequencies), and structure models, which use abstract phonological generalizations (such as a ban on [coronal][coronal] sequences). Listeners (N=16 in each experiment) judged synthetic 6 x 6 arrays of stop-sonorant clusters in which both consonants were ambiguous. The effect of the stop judgment on the log odds ratio of the sonorant judgment was assessed separately for each stimulus token to provide a stimulus-independent measure of bias. Experiment 1 compared perceptual bias against the onsets [bw] and [dl], which violate different structural constraints but are both of zero frequency. Experiment 2 compared bias against [dl] in CCV and VCCV contexts, to investigate the interaction of syllabification with segmentism and to rule out a compensation-for-coarticulation account of Experiment 1. Results of both experiments favor the structure models (supported by NSF).     

Phonological processes and the perception of phonotactically illegal consonant clusters

The perception of consonant clusters that are phonotactically illegal word initially in English (e.g., /tl/, /sr/) was investigated to determine whether listeners’ phonological knowledge of the language influences speech processing. Experiment 1 examined whether the phonotactic context effect (Massaro & Cohen, 1983), a bias toward hearing illegal sequences (e.g., /tl/) as legal (e.g., /tr/), is more likely due to knowledge of the legal phoneme combinations in English or to a frequency effect. In Experiment 2, Experiment 1 was repeated with the clusters occurring word medially to assess whether phonotactic rules of syllabification modulate the phonotactic effect. Experiment 3 examined whether vowel epenthesis, another phonological process, might also affect listeners’ perception of illegal sequences as legal by biasing them to hear a vowel between the consonants of the cluster (e.g., /talee/). Results suggest that knowledge of the phonotactically permissible sequences in English can affect phoneme processing in multiple ways.     

Better the DVL you know: acronyms reveal the contribution of familiarity to single-word reading

Current theories of reading are divided between dual-route accounts, which propose that separable processes subserve word recognition for orthographically regular and irregular strings, and connectionist models, which propose a single mechanism mapping form to meaning. These theories make distinct predictions about the processing of acronyms, which can be orthographically illegal and yet familiar, as compared with the processing of pseudowords, which are regular but unfamiliar. This study examined whether acronyms are processed like pseudowords and words. Event-related potentials (ERPs) were recorded as subjects viewed familiar and unfamiliar acronyms, words, pseudowords, illegal strings, and--as the targets of the substantive behavioral task--proper names. Familiar acronyms elicited repetition effects on the N400 component, a functionally specific index of semantic activation processes; repetition effects for familiar acronyms were similar in magnitude, timing, and scalp distribution to those for words and pseudowords. The similarity of the brain response to familiar--but--illegal and unfamiliar--but--legal classes of stimuli is inconsistent with predictions of dual-route models of reading.     

Constraints on statistical computations at 10 months of age: the use of phonological features

Recently, several studies have argued that infants capitalize on the statistical properties of natural languages to acquire the linguistic structure of their native language, but the kinds of constraints which apply to statistical computations remain largely unknown. Here we explored French‐learning infants' perceptual preference for labial‐coronal (LC) words over coronal‐labial words (CL) words (e.g. preferring bat over tab) to determine whether this phonotactic preference is based on the acquisition of the statistical properties of the input based on a single phonological feature (i.e. place of articulation), multiple features (i.e. place and manner of articulation), or individual consonant pairs. Results from four experiments revealed that infants had a labial‐coronal bias for nasal sequences (Experiment 1) and for all plosive sequences (Experiments 2 and 4) but a coronal‐labial bias for all fricative sequences (Experiments 3 and 4), independently of the frequencies of individual consonant pairs. These results establish for the first time that constellations of multiple phonological features, defining broad consonant classes, constrain the early acquisition of phonotactic regularities of the native language.     

Native and Non-native Speakers’ Brain Responses to Filled Indirect Object Gaps

We examined native and non-native English speakers’ processing of indirect object wh-dependencies using a filled-gap paradigm while recording event-related potentials (ERPs). The non-native group was comprised of native German-speaking, proficient non-native speakers of English. Both participant groups showed evidence of linking fronted indirect objects to the subcategorizing verb when this was encountered, reflected in an N400 component. Evidence for continued filler activation beyond the verb was seen only in the non-native group, in the shape of a prolonged left-anterior negativity. Both participant groups showed sensitivity to filled indirect object gaps reflected in a P600 response, which was more pronounced and more globally distributed in our non-native group. Taken together, our results indicate that resolving indirect object dependencies is a two-step process in both native and non-native sentence comprehension, with greater processing cost incurred in non-native compared to native comprehension.     

Perceptual and response components in repetition priming of spoken words and pseudowords

Two experiments explored repetition priming effects for spoken words and pseudowords in order to investigate abstractionist and episodic accounts of spoken word recognition and repetition priming. In Experiment 1, lexical decisions were made on spoken words and pseudowords with half of the items presented twice (～12 intervening items). Half of all repetitions were spoken in a “different voice” from the first presentations. Experiment 2 used the same procedure but with stimuli embedded in noise to slow responses. Results showed greater priming for words than for pseudowords and no effect of voice change in both normal and effortful processing conditions. Additional analyses showed that for slower participants, priming is more equivalent for words and pseudowords, suggesting episodic stimulus–response associations that suppress familiarity-based mechanisms that ordinarily enhance word priming. By relating behavioural priming to the time-course of pseudoword identification we showed that under normal listening conditions (Experiment 1) priming reflects facilitation of both perceptual and decision components, whereas in effortful listening conditions (Experiment 2) priming effects primarily reflect enhanced decision/response generation processes. Both stimulus–response associations and enhanced processing of sensory input seem to be voice independent, providing novel evidence concerning the degree of perceptual abstraction in the recognition of spoken words and pseudowords.     

Electrophysiological evidence for priming in response to words and pseudowords in first and second language

The study purpose was to indicate when language-specific processing first occurs and how first and second language priming processes interact. Event-related potentials were recorded from 14 normal native Hebrew speakers, in a variation of lexical decision task, to pairs of stimuli (S1, S2) in Hebrew, English, Hebrew pseudowords, and English pseudowords. Although no behavioral priming was observed, priming by pseudowords in either language affected both N400 and the late positive component of event related potential. N1 and P2 latencies were longer to S2 in semantically related pairs, indicating that language-specific processing may take place as early as auditory cortex. Different processing of first and second language was evident only in response to pseudowords.     

Phonetic, phonemic, and phonological factors in cross-language discrimination of phonotactic contrasts

Previous research indicates that multiple levels of linguistic information play a role in the perception and discrimination of non-native phonemes. This study examines the interaction of phonetic, phonemic and phonological factors in the discrimination of non-native phonotactic contrasts. Listeners of Catalan, English, and Russian are presented with an initial #CC-#C?C contrast in a discrimination task. For the Catalan group, the phonemes and their phonetic implementation were native, but the #CC phonotactics were not. For Russian listeners, the phonemes and phonetic implementation were not native but Russian allows a large number of #CC sequences. For English listeners, none of the phonetics, phonemes, nor phonotactics are native. Two task variables, stimuli length and order of presentation, were also manipulated. Results showed that the Russian listeners were most accurate overall, suggesting that the presence of the phonotactic structure in the listeners' native language may be more important than either phonemic or phonetic information. The interaction between the task manipulations and the linguistic variables is also addressed.     

All parts of an item are not equal: Effects of phonological redundancy on immediate recall

The process of redintegration is thought to use top-down knowledge to repair partly damaged memory traces. We explored redintegration in the immediate recall of lists from a limited pool of partly phonologically redundant pseudowords. In Experiment 1, four kinds of stimuli were created by adding the syllable /ne/ to two-syllable pseudowords, either to the middle (/tepa/ vs. /tenepa/) or to the end (/tepane/), or adding a different syllable to each item (/tepalo/, /vuropi/). The repeated syllable was thought to be available for redintegration. Lists of two-syllable pseudowords were recalled best, items with a redundant end were intermediate, and items with a redundant middle-syllable were as hard as nonredundant three-syllable items. In Experiment 2, the last syllable was predictable from context but not shared between all stimuli, reducing phonological similarity between items. Performance did not differ from the situation with identicallast syllables. In Experiment 3, a shared first syllable had a detrimental effecton memory. An error analysis showed that beneficial redundancy effects were accompanied by harmful similarity effects, impairing memory for nonredundant syllables. The balance between the two effects depended on syllable position.     

Sensitivity to Crossover Constraints During Native and Non-native Pronoun Resolution

We report the results from two experiments examining native and non-native German speakers’ sensitivity to crossover constraints on pronoun resolution. Our critical stimuli sentences contained personal pronouns in either strong (SCO) or weak crossover (WCO) configurations. Using eye-movement monitoring during reading and a gender-mismatch paradigm, Experiment 1 investigated whether a fronted wh-phrase would be considered as a potential antecedent for a pronoun intervening between the wh-phrase and its canonical position. Both native and non-native readers initially attempted coreference in WCO but not in SCO configurations, as evidenced by early gender-mismatch effects in our WCO conditions. Experiment 2 was an offline antecedent judgement task whose results mirrored the SCO/WCO asymmetry observed in our reading-time data. Taken together, our results show that the SCO constraint immediately restricts pronoun interpretation in both native and non-native comprehension, and further suggest that SCO and WCO constraints derive from different sources.     

Sensitivity to Phonological Similarity Within and Across Languages

The influence of phonological similarity on bilingual language processing was examined within and across languages in three experiments. Phonological similarity was manipulated within a language by varying neighborhood density, and across languages by varying extent of cross-linguistic overlap between native and non-native languages. In Experiment 1, speed and accuracy of bilinguals’ picture naming were susceptible to phonological neighborhood density in both the first and the second language. In Experiment 2, eye-movement patterns indicated that the time-course of language activation varied across phonological neighborhood densities and across native/non-native language status. In Experiment 3, speed and accuracy of bilingual performance in an auditory lexical decision task were influenced by degree of cross-linguistic phonological overlap. Together, the three experiments confirm that bilinguals are sensitive to phonological similarity within and across languages and suggest that this sensitivity is asymmetrical across native and non-native languages and varies along the timecourse of word processing.     

Language-specific listening

Languages differ in their phonological structure and physcholinguists have begun to explore the conseqence, of this fact for speech perception. We review research documenting that listeners attune their perceptual processes finaly to exploit the phonological regularities of their nativ language. As a consequence, these perceptual process are fill-adapted to listening to languages that do not display such, regularities. Thus, not only do late language-learners have trouble speaking a second language, also they do not hear it as native speakers do; worse, they apply their native language listening prosedures which may actually interfere with successful processing of the non-native input. We also present data from studies on infants showing that the initial attuning occurs early in life; very yong infants are sensitive to the relevant phonological regularities which distinguish different languages, and quickly distinguish the native language of their environment from languages with different regularities.     

The Role of Natural Class Features in the Acquisition of Phonotactic Regularities

Previous research has shown that phonotactic regularities can be acquired through recent production or auditory experience (e.g., Dell et  al., Journal of Experimental Psychology: Learning, Memory, and Cognition, 26(6), 1355–1367, 2000; Onishi et al., Cognition, 83(1), B13–B23, 2002). However, little is known about the role of phonological natural classes in this learning process. This study addressed this question by investigating the acquisition of a contingency relationship between onsets and medial glides by Mandarin speakers. The experiments involved the manipulation of three types of phonotactic regularities. In the Laryngeal version, onsets that preceded the same glide shared a voicing feature. In the Place version, onsets that preceded same glide shared a place feature. In the Neither version, onsets associated with the same glide shared neither a voicing feature nor a place feature. Results showed the Place version and the Laryngeal version were more easily acquired than the Neither version in terms of the amount of exposure needed to acquire the experimentally manipulated phonotactic schema and the sustainability of the acquired schema. The results suggest that the statistical learning mechanism that guides our processing of speech input prefers phonological regularities that follow certain natural class features. This preference may account for the way natural languages are structured phonologically. An erratum to this article can be found at     

The N400 and the fourth grade shift

While behavioral and educational data characterize a fourth grade shift in reading development, neuroscience evidence is relatively lacking. We used the N400 component of the event‐related potential waveform to investigate the development of single word processing across the upper elementary years, in comparison to adult readers. We presented third graders, fourth graders, fifth graders, and college students with a well‐controlled list of real words, pseudowords, letter strings, false font strings, and animal name targets. Words and pseudowords elicited similar N400s across groups. False font strings elicited N400s similar to words and letter strings in the three groups of children, but not in college students. The pattern of findings suggests relatively adult‐like semantic and phonological processing by third grade, but a long developmental time course, beyond fifth grade, for orthographic processing in this context. Thus, the amplitude of the N400 elicited by various word‐like stimuli does not reflect some sort of shift or discontinuity in word processing around the fourth grade. However, the results do suggest different developmental time courses for the processes that contribute to automatic single word reading and the integrative N400.     

Building phonotactic knowledge in bilinguals: role of early exposure

Timing and amount of exposure to a 2nd language in the acquisition of phonotactic restrictions was examined in 4 experiments. In Experiments 1 and 2, 10-month-old monolingual and bilingual Catalan-Spanish infants were presented with nonwords that were phonotactically legal or illegal in Catalan and phonotactically illegal in Spanish. Differences between the 4 groups of infants were obtained as a function of language dominance. In Experiments 3 and 4, adult Spanish-Catalan bilinguals were compared with the same materials. Catalan-dominant bilinguals were more accurate than Spanish-dominant bilinguals in their perception of legal sequences; however, they were not more accurate with illegal sequences. The findings suggest a complex correlation between the pattern of preference and the amount and timing of exposure.     

Infants learn phonotactic regularities from brief auditory experience

Two experiments investigated whether novel phonotactic regularities, not present in English, could be acquired by 16.5-month-old infants from brief auditory experience. Subjects listened to consonant-vowel-consonant syllables in which particular consonants were artificially restricted to either initial or final position (e.g. /baep/ not /paeb/). In a later head-turn preference test, infants listened longer to new syllables that violated the experimental phonotactic constraints than to new syllables that honored them. Thus, infants rapidly learned phonotactic regularities from brief auditory experience and extended them to unstudied syllables, documenting the sensitivity of the infant's language processing system to abstractions over linguistic experience.     

Implicit Segmentation of a Stream of Syllables Based on Transitional Probabilities: An MEG Study

Statistical segmentation of continuous speech, i.e., the ability to utilise transitional probabilities between syllables in order to detect word boundaries, is reflected in the brain’s auditory event-related potentials (ERPs). The N1 and N400 ERP components are typically enhanced for word onsets compared to random syllables during active listening. We used magnetoencephalography (MEG) to record event-related fields (ERFs) simultaneously with ERPs to syllables in a continuous sequence consisting of ten repeating tri-syllabic pseudowords and unexpected syllables presented between these pseudowords. We found the responses to differ between the syllables within the pseudowords and between the expected and unexpected syllables, reflecting an implicit process extracting the statistical characteristics of the sequence and monitoring for unexpected syllables.     

Sublexical ambiguity effect in reading Chinese disyllabic compounds

For Chinese compounds, neighbors can share either both orthographic forms and meanings, or orthographic forms only. In this study, central presentation and visual half-field (VF) presentation methods were used in conjunction with ERP measures to investigate how readers solve the sublexical semantic ambiguity of the first constituent character in reading a disyllabic compound. The sublexical ambiguity of the first character was manipulated while the orthographic neighborhood sizes of the first and second character (NS1, NS2) were controlled. Subjective rating of number of meanings corresponding to a character was used as an index of sublexical ambiguity. Results showed that low sublexical ambiguity words elicited a more negative N400 than high sublexical ambiguity words when words were centrally presented. Similar patterns were found when words were presented to the left VF. Interestingly, different patterns were observed for pseudowords. With left VF presentation, high sublexical ambiguity psudowords showed a more negative N400 than low sublexical ambiguity pseudowords. In contrast, with right VF presentation, low sublexical ambiguity pseudowords showed a more negative N400 than high sublexical ambiguity pseudowords. These findings indicate that a level of morphological representation between form and meaning needs to be established and refined in Chinese. In addition, hemispheric asymmetries in the use of word information in ambiguity resolution should be taken into account, even at sublexical level.