Lexical Lookup Research Articles

Neural responses to Finnish inflected forms during overt and covert production: The role of stem frequency and stem allomorphy

Despite extensive behavioral research on complex word recognition, the neural mechanisms involved in the production of inflections in agglutinative languages, such as Finnish, are still poorly understood. Finnish inflected nouns typically involve morphophonological alternations of the stem (i.e. consonant gradation; CG), which is less common in other languages. Behavioral research on recognition of inflected nouns containing consonant gradation has shown that the number of stem allomorphs results in faster recognition times. To our knowledge, no functional magnetic resonance imaging (fMRI) studies have explicitly investigated consonant gradation in word production. In this study, participants performed covert and overt production tasks during event-related fMRI. Our stimuli comprised real word stems of high and medium frequency as well as pseudoword stems. The stems either included consonant gradation or were non-gradating. Our findings showed that the production of inflected forms containing high frequency stems or CG stems (irrespective of frequency and lexicality) yield enhanced activation of the left inferior frontal and middle frontal gyri (LIFG and MFG, respectively). This suggests that CG stems, that is, stems with more than one allomorph, facilitate lexical lookup, and that the activation of multiple stem allomorphs is reflected in increased recruitment of frontal brain regions. • We examined the effect of stem allomorphy on Finnish inflected word production. • Stem allomorphy increases error rates when producing gradated inflected forms. • Gradated stems cause stronger LIFG/MFG activation compared to non-gradated. • Higher LIFG/MFG activation was present for real stems compared to pseudo-stems. • This robust frontal activation may underpin lexical allomorph access.

Stress priming in reading and the selective modulation of lexical and sub-lexical pathways.

Four experiments employed a priming methodology to investigate different mechanisms of stress assignment and how they are modulated by lexical and sub-lexical mechanisms in reading aloud in Italian. Lexical stress is unpredictable in Italian, and requires lexical look-up. The most frequent stress pattern (Dominant) is on the penultimate syllable [laVOro (work)], while stress on the antepenultimate syllable [MAcchina (car)] is relatively less frequent (non-Dominant). Word and pseudoword naming responses primed by words with non-dominant stress – which require whole-word knowledge to be read correctly – were compared to those primed by nonwords. Percentage of errors to words and percentage of dominant stress responses to nonwords were measured. In Experiments 1 and 2 stress errors increased for non-dominant stress words primed by nonwords, as compared to when they were primed by words. The results could be attributed to greater activation of sub-lexical codes, and an associated tendency to assign the dominant stress pattern by default in the nonword prime condition. Alternatively, they may have been the consequence of prosodic priming, inducing more errors on trials in which the stress pattern of primes and targets was not congruent. The two interpretations were investigated in Experiments 3 and 4. The results overall suggested a limited role of the default metrical pattern in word pronunciation, and showed clear effect of prosodic priming, but only when the sub-lexical mechanism prevailed.

Duration and context speech rate as cues to lexical perception and word segmentation.

Duration and speech rate are traditionally assumed to be filtered out before lexical lookup takes place, although these factors are known to influence phoneme perception. Here, the hypothesis was investigated that duration can affect both perceived lexical identity, as well as the perceived number and implied locations of word boundaries relative to the speech signal. Experiment 1 was a production study which investigated durations of vocalic portions of phonetically similar versions of target word strings which differed in their number of syllables (e.g., cease versus see us); these target word strings were spoken in semantically neutral context sentences. As expected, vocalic durations in target strings with fewer syllables were shorter than those with more syllables. In Experiment 2, the relative durations of vocalic portions of target strings in sentences from Experiment 1, as well as sentential context speech rate, were manipulated using speech resynthesis. Relative duration and context speech rate both affected the words that participants heard, as well as the implied number of phonemes and imputed locations of word boundaries. These findings indicate that duration plays a significant and underinvestigated role in spoken word recognition and word segmentation.

Beyond the two-strategy model of skilled spelling: effects of consistency, grain size, and orthographic redundancy.

Most models of spelling assume that people rely on two procedures when engaging in spelling: a lexical look-up procedure that retrieves spellings in their entirety, and a nonlexical procedure that constructs spellings with a set of phoneme-grapheme rules. In the present research, we investigated whether larger sized subsyllabic relationships also play a role in spelling, and how they compare to small-sized phoneme-grapheme relationships. In addition, we investigated whether purely orthographic units can explain some of the variance typically attributed to the mapping between sound and spelling. To do this, we ran five spelling experiments, two using real words and three using nonwords. Results from the experiments showed that there were independent contributions of both phoneme-grapheme and larger sized subsyllabic sound-spelling relationships, although the effect of phoneme-grapheme-sized relationships was always stronger and more reliable than larger sized subsyllabic sound-spelling relationships. Purely orthographic effects were also shown to affect word spelling, but no significant effects were found with nonword spelling. Together, the results support the hypothesis that a major constraint on spelling comes from phoneme-grapheme-sized relationships.

Stress regularity or consistency? Reading aloud Italian polysyllables with different stress patterns

Stress assignment to three- and four-syllable Italian words is not predictable by rule, but needs lexical look-up. The present study investigated whether stress assignment to low-frequency Italian words is determined by stress regularity, or by the number of words sharing the final phonological segment and the stress pattern (stress neighborhood or consistency). Experiment 1 showed an effect of stress neighborhood: words were read aloud faster and more accurately when they had a prevalence of stress “friends,” irrespective of stress regularity. Moreover, when irregularly stressed words have a higher number of stress friends compared to regularly stressed words, they are read even faster (Experiment 2). In Experiment 3, using visual lexical decision, no difference related to the numerosity of stress friends was found. It is concluded that reading aloud Italian low-frequency words with different stress patterns is mainly affected by the numerosity of lexical types that share a given final sequence and the stress pattern. The phonological nature of the numerosity of lexical representations affecting reading aloud finds support in the absence of such effect in visual lexical decision. These results have implications for models of reading aloud that go beyond monosyllables.

L2 Processing of Dutch regular and irregular Verbs

Abstract Do Ll and (advanced) L2 speakers of Dutch employ distinct processes — rule application for regulars and lexical lookup for irregulars — when producing Dutch past tense forms? Do L2 speakers of a language that observes the same dual conjugation system as in Dutch (e.g. English, German) produce Dutch past tenses by a different process (i.e. more like that of Ll speakers) than learners of Dutch with a different Ll verb system (e.g. Japanese and Chinese)? We studied the on-line past tense production performance of Ll speakers and of advanced L2 speakers of Dutch varying relative past tense frequency of regular and irreg-ular Dutch verbs. Performance proved slower and less accurate with both Ll and L2 speakers for irregular verbs with relatively low past tense frequency. No frequency effects were found for regular verbs. The results were qualitatively the same for English/German and for Japanese/Chinese L2 speakers, with a striking tendency to overgeneralize the regular past tense formation. We conclude that the mental representation of the Dutch past tense rule is essentially the same for Ll and L2 language users.

A Common Conceptual Code In Bilinguals: Evidence From Simultaneous Interpretation

Two prominent views of the relations between a bilingual’s language repertoires lead to different accounts of simultaneous interpretation. According to the “lexical hypothesis,” interpretation employs links between lexical equivalents in the bilingual speaker’s two lexicons. According to the “conceptual mediation hypothesis,” interpretation engages conceptual structures shared by the two lexicons. Simultaneous interpretation was compared to transliteration, which models the essential aspect of the lexical hypothesis; i.e. the process of rapid lexical lookup of translation equivalents. In an experiment using cloze completions that required either simple recall or inferences, subjects were less accurate in making inferences than in recalling information in both the interpreting and the transliterating tasks, but the difference between recall and inference was larger in the transliterating task. This interaction between task and cloze type indicates that different processes mediate interpretation and transliteration and thus weakens the lexical hypothesis as an account of simultaneous interpretation. This finding provides support to logical arguments that claim that direct links between a bilingual’s two lexicons are not sufficient to explain simultaneous interpretation.

Computational Morphology: Practical Mechanisms for the English Lexicon

Part 1 Introduction: the need for a computational lexicon what is the lexicon? morphology segmentation and orthography word structure the unit of storage lexical redundancy preprocessing and look-up what this book is about. Part 2 Morphographemics: generative phonology formalizing phonological rules transducers the two-level model the transducer version the two-level rule notation the lexicon and word grammar interface formal issues. Part 3 Word structure rules: context free rules features and categories the word structure formalism varieties of unification the term unification enhancements the role of the word grammar an illustrative. Part 4 Feature propagation in the word grammar: beyond structural rules other theories of feature propagation feature-passing conventions usefulness of conventions. Part 5 Lexical rules: lexicon expansion the role of lexical rules format of lexical rules completion rules multiplication rules consistency checks application of lexical rules lexicon management the advantages of lexical rules. Part 6 A description of English: overview of the model what is a morpheme? stems and affixes morphographemics lexical rules and defaults syntactic features inflection and derivation classifying words the word grammar feature conventions illustrative examples over-generation a caveat. Part 7 The implemented system: facilities provided the lexicon spelling rules the word grammar the analysis process dictionary command interpreter other implementation issues practical considerations. Part 8 Limitations and extensions: spelling rules word grammar and feature conventions lexical entries and rules idioms compounds irregularity and blocking the implemented system. Appendices: definition of the linguistic notation syntactic and morphological features some sample lexical entries a description of English morphology sample results of lexical look-up formal definitions complexity of two-level morphology.

Software systems for Computational Morphology—An Overview

Representative sets of software systems for computational morphology are evaluated as candiates for a general morphological program module in the context of computer-aided word class tagging. They are considered as both programming tools and representations of linguistic Knowledge. The systems, which are found to be relatively neutral with respect to linguistic theory, can be grouped into a general-purpose and a special-purpose type. Pattern matching in them is described as a high-level feature applied to the computational treatment of phenomena characteristic of morphological analysis: lexical lookup, morphotactics, and morphophonemic alternation. The systems are found to perform similarly in simple applications, but significantly differently in more complicated ones where integrated and well-structured solutions are sought.

Knowledge representation for automated understanding of natural language discourse

levels, such as Pet6fi's text grammar and Rumelhart's schemata for stories. By defining permissible interrelations between constituents of larger texts at all levels of abstraction, these create meaning structures organized on both hierarchical and associative principles, rather than on a sequential basis. The automated "understanding" process consists of instantiating an appropriate set of event templates by associating a given text with the ERGO inventory of event templates and const ucting a network of instanti ted templates based on intertemplate relational rules and constraints. The network of instantiated t mplates thus represents the information content of the unstructured original text, and provides the structured input for the event record data bas . Details of the automated understanding process presented here in the abstract are given in the follo ing section. 3.2 Processing Principles. The process of data base generation involves two major functions: (1) co tent analysis of the incoming text (2) event record synthesis (or production) The first involves constructing a meaning representation of the text and the second the extraction of relevant information and its storage in a data base record. The major focus of ERGO is on reports of a particular class of events which describe aircraft movements. The unit of analysis is therefore the report, a textual unit consisting of one or more par graphs, each containing one or more sentences. The first step in the analytical process involves a lexical lookup: a lexical entry contains morphological, syntactic and semantic information, on the lines of Sager (1973) and Stockwell et al. (1973). Each sentence is then subjected to a syntactic analysis by means of an Augmented Transition Network (ATN) parser (Woods, 1970). Since event templates are based on propositional structures, the analytical

Structure of a complete text‐to‐speech system

The structure of a complete text‐to‐speech system, including lexical lookup, morphological analysis, parts‐of‐speech determination, parsing, letter‐to‐sound rules, lexical and phrase‐level stress, morphophonemic rules, pitch and timing rules, and phonemic synthesis is presented. The interrelation of these processes is stressed, and the current status of the algorithm is described in relation to the quality of the speech output. Practical implementations (e.g., in computer terminals, or reading machines for the blind) are also presented, including special purpose hardware. The design of these specialized devices is shown to be related to the structure of the algorithms to be implemented.

Patterns of paralexia: a psycholinguistic approach.

A sample of the literature on acquired dyslexia is reviewed with special reference to the nature of paralexic errors. Linguistic studies of six cases of dyslexia are presented, with appropriate neurological and psychological details; there are two cases of each of three hypothesized types of impairment, visual dyslyxia, “surface” (grapheme-phoneme) dyslexia, and “deep” (syntactico-semantic) dyslexia. Finally, a scheme for acquired dyslexia is proposed and related to the error patterns observed in “normal” adult readers and in children learning to read; our approach to lexical look-up is one that the diagram makers may have found sympathique.