What "mice trap" tells us about the mental lexicon

Level ordering has proven inadequate as a morphological theory, leaving unexplained the experimental results taken to support it as a component of innate grammar-young children's acceptance of irregular plurals in English compounds. The present study demonstrates that these results can be explained by slower access to the grammatically preferred singulars of irregular nouns when compounds are created on-line from plural stimuli. Experiments on English noun-noun compound production and on production of either singular or plural forms from the same or opposite form confirmed that more irregular than regular plurals were used in compounds, and showed that producing irregular singulars from plurals was slower than producing regular singulars. Plural responses were also slower when cue and required response number differed.     

Regular and irregular inflection in the acquisition of German noun plurals.

In this paper we study the acquisition of German noun plurals in relation to the question of how children represent regular and irregular inflection. Pinker and Prince (1992) have demonstrated several dissociations between regular and irregular inflection in the English past tense system. However, in English, the default status of -ed is confounded with its high frequency; therefore inflectional systems other than English past tense formation must be examined. The noun plural system in German is particularly interesting, because most nouns have irregular plurals in German and the regular (default) plural is less frequent than several of the irregular plurals. Thus it is unclear how a language learner determines whether German even has a regular plural, and if so what form it takes. Based on longitudinal data from impaired and unimpaired monolingual German-speaking children, we find a striking, statistically significant correlation: plural affixes that are used in overregularizations, namely -n or -s, are left out within compounds. This correlation shows that even impaired children are sensitive to the distinction between regular and irregular morphology. We propose a linguistic analysis of the correlation in terms of Kiparsky's (1982, 1985) level-ordering model plus an additional ordering condition on affixes: default (regular) affixes cannot serve as input to compounding processes.     

Modality effects in compounding with English inflectional morphology

The treatment of plural morphemes in English noun–noun compounds is significant because it provides a test case for competing theories of language acquisition and representation. Even when the first noun in a compound refers to plural items, native speakers frequently use the singular form ( Murphy, 2000 ). Sometimes, they will use the irregular plural form (‘mice chaser’) but very rarely are regular plurals (‘rats chaser’) used as the first noun in a compound. This effect has been found with native English‐ speaking children ( Gordon, 1985 ; Nicoladis, 2000 ; Oetting & Rice, 1993 ; van der Lely & Christian, 2000 ); native English‐speaking teenagers ( van der Lely & Christian, 2000 ); and native English‐speaking adults ( Lardiere & Schwartz, 1997 ; Murphy, 2000 ). The apparent dissociation between regular and irregular plurals (i.e. that irregular plurals are included before a second noun but regular plurals are almost never included before a second noun) is thought to be due to innate morphological constraints ( Marcus, Brinkmann, Clahsen, Weise, & Pinker, 1995 ). Such constraints predict that all items of regular morphology should be treated differently from all items of irregular morphology by language users in all situations. However, if external factors such as input and response modality affect the number of plurals included in compounds, then this questions the internal constraint‐based explanations of compounding and encourages investigation of how external factors might influence the number of plurals included in compounds.     

Learning language from the input: why innate constraints can't explain noun compounding

Do the production and interpretation of patterns of plural forms in noun-noun compounds reveal the workings of innate constraints that govern morphological processing? The results of previous studies on compounding have been taken to support a number of important theoretical claims: first, that there are fundamental differences in the way that children and adults learn and process regular and irregular plurals, second, that these differences reflect formal constraints that govern the way the way regular and irregular plurals are processed in language, and third, that these constraints are unlikely to be the product of learning. In a series of seven experiments, we critically assess the evidence that is cited in support of these arguments. The results of our experiments provide little support for the idea that substantively different factors govern the patterns of acquisition, production and interpretation patterns of regular and irregular plural forms in compounds. Once frequency differences between regular and irregular plurals are accounted for, we find no evidence of any qualitative difference in the patterns of interpretation and production of regular and irregular plural nouns in compounds, in either adults or children. Accordingly, we suggest that the pattern of acquisition of both regular and irregular plurals in compounds is consistent with a simple account, in which children learn the conventions that govern plural compounding using evidence that is readily available in the distribution patterns of adult speech.     

Level-ordering does not constrain children’s ungrammatical compounds

English-speaking children typically avoid using regular plurals in novel grammatical deverbal compounds as in rat eater but allow irregular plurals as in mice eater (Gordon, 1985). To explain these data, it has been argued that Kiparsky’s (1983) level-ordering model constrains the production of morphologically complex words, including those with which children have had little to no experience. If level-ordering can be supported, children should avoid regular plurals in their ungrammatical deverbal compounds like a breaker-bottle. Seventy-two English-speaking children were included in the present study, 36 from Britain and 36 from Canada. The results showed that 50% of the children who produced ungrammatical compounds included regular plurals in the compounds they produced. Conversely, none of the children who produced grammatical compounds included regular plurals. These results indicate that level-ordering does not constrain children’s production of ungrammatical compounds. These results raise the possibility that level-ordering may not be a valid constraint of children’s compounding in general.     

A functional analysis of receptive language and productive speech: acquisition of the plural morpheme

Operant conditioning procedures were applied to two retardates to establish receptive auditory plurals: correct pointing to single or paired objects was reinforced after hearing singular or plural labels. This training proceeded until an errorless (generative) criterion of correct performance was achieved. Unreinforced probes measuring expressive use of singulars and plurals were interspersed in this receptive training. Neither subject generalized from this receptive training to expressive plurals, in that each used singulars when labeling pairs. Then, both subjects were directly trained in conventional expressive plurals to an errorless (generative) criterion. The previous design was then repeated, but the receptive repertoire was reversed: pointing at pairs in response to singular labels was reinforced, and vice-versa. Unreinforced probes of expressive plural usage again showed its independence of the current receptive repertoire in that conventional (unreversed) plural usage was displayed. Thus, the independence of the expressive repertoire (even when unreinforced) from the reinforced patterns of the receptive repertoire was demonstrated.     

Level-ordering does not constrain children's ungrammatical compounds

English-speaking children typically avoid using regular plurals in novel grammatical deverbal compounds as in rat eater but allow irregular plurals as in mice eater (Gordon, 19985). To explain these data, it has been argued that level-ordering model constrains the production of morphologically complex words, including those with which children have had little to no experience. If level-ordering can be supported, children should avoid regular plurals in their ungrammatical deverbal compounds like a breaker-bottle. Seventy-two English-speaking children were included in the present study, 36 from Britain and 36 from Canada. The results showed that 50% of the children who produced ungrammatical compounds included regular plurals in the compounds they produced. Conversely, none of the children who produced grammatical compounds included regular plurals. These results indicate that level-ordering does not constrain children's production of ungrammatical compounds. These results raise the possibility that level-ordering may not be a valid constraint of children's compounding in general.     

Language learning and innateness: some implications of Compounds Research

In noun compounds in English, the modifying noun may be singular (mouse-eater) or an irregularly inflected plural (mice-eater), but regularly inflected plurals are dispreferred (*rats-eater). This phenomenon has been taken as strong evidence for dual-mechanism theories of lexical representations, which hold that regular (rule-governed) and irregular (exception) items are generated by qualitatively different and innately specified mechanisms. Using corpus analyses, behavioral studies, and computational modeling, we show that the rule-versus-exceptions approach makes a number of incorrect predictions. We propose a new account in which the acceptability of modifiers is determined by a constraint satisfaction process modulated by semantic, phonological, and other factors. The constraints are acquired by the child via general purpose learning algorithms, based on noun compounds and other constructions in the input. The account obviates the regular/irregular dichotomy while simultaneously providing a superior account of the data.     

One or more: psycholinguistic evidence for divergence of numerosity and grammatical number assignment.

Naturalistic slips of the tongue in Finnish were studied in order to reveal the production of grammatical number. It appears that speakers may consider plural forms referring to single events as singulars and collective nouns as plurals. These result in violations in number agreement. It was found that errors in numerosity are both structural and semantic in nature and that one type can be traced to the level of morphological encoding and the other type to message formulation.     

Experience and grammatical agreement: Statistical learning shapes number agreement production

A robust result in research on the production of grammatical agreement is that speakers are more likely to produce an erroneous verb with phrases such as the key to the cabinets, with a singular noun followed by a plural one, than with phrases such as the keys to the cabinet, where a plural noun is followed by a singular. These asymmetries are thought to reflect core language production processes. Previous accounts have attributed error patterns to a syntactic number feature present on plurals but not singulars. An alternative approach is presented in which a process similar to structural priming contributes to the error asymmetry via speakers’ past experiences with related agreement constructions. A corpus analysis and two agreement production studies test this account. The results suggest that agreement production is shaped by statistical learning from past language experience. Implications for accounts of agreement are discussed.     

Deaf and hearing children's plural noun spelling

The present study examines deaf and hearing children's spelling of plural nouns. Severe literacy impairments are well documented in the deaf, which are believed to be a consequence of phonological awareness limitations. Fifty deaf (mean chronological age 13;10 years, mean reading age 7;5 years) and 50 reading-age-matched hearing children produced spellings of regular, semiregular, and irregular plural nouns in Experiment 1 and nonword plurals in Experiment 2. Deaf children performed reading-age appropriately on rule-based (regular and semiregular) plurals but were significantly less accurate at spelling irregular plurals. Spelling of plural nonwords and spelling error analyses revealed clear evidence for use of morphology. Deaf children used morphological generalization to a greater degree than their reading-age-matched hearing counterparts. Also, hearing children combined use of phonology and morphology to guide spelling, whereas deaf children appeared to use morphology without phonological mediation. Therefore, use of morphology in spelling can be independent of phonology and is available to the deaf despite limited experience with spoken language. Indeed, deaf children appear to be learning about morphology from the orthography. Education on more complex morphological generalization and exceptions may be highly beneficial not only for the deaf but also for other populations with phonological awareness limitations.     

The nature of regularity and irregularity: evidence from Hebrew nominal inflection

Most evidence for the role of regular inflection as a default operation comes from languages that confound the morphological properties of regular and irregular forms with their phonological characteristics. For instance, regular plurals tend to faithfully preserve the base's phonology (e.g., rat-rats), whereas irregular nouns tend to alter it (e.g., mouse-mice). The distinction between regular and irregular inflection may thus be an epiphenomenon of phonological faithfulness. In Hebrew noun inflection, however, morphological regularity and phonological faithfulness can be distinguished: Nouns whose stems change in the plural may take either a regular or an irregular suffix, and nouns whose stems are preserved in the plural may take either a regular or an irregular suffix. We use this dissociation to examine two hallmarks of default inflection: its lack of dependence on analogies from similar regular nouns, and its application to nonroots such as names. We show that these hallmarks of regularity may be found whether or not the plural form preserves the stem faithfully: People apply the regular suffix to novel nouns that do not resemble existing nouns and to names that sound like irregular nouns, regardless of whether the stem is ordinarily preserved in the plural of that family of nouns. Moreover, when they pluralize names (e.g., the Barak-Barakim), they do not apply the stem changes that are found in their homophonous nouns (e.g., barak-brakim lightning), replicating an effect found in English and German. These findings show that the distinction between regular and irregular phenomena cannot be reduced to differences in the kinds of phonological changes associated with those phenomena in English. Instead, regularity and irregularity must be distinguished in terms of the kinds of mental computations that effect them: symbolic operations versus memorized idiosyncrasies. A corollary is that complex words are not generally dichotomizable as regular or irregular different aspects of a word may be regular or irregular depending on whether they violate the rule for that aspect and hence must be stored in memory.     

An analysis of individual differences in generalization between receptive and productive language in retarded children

Retarded subjects were taught generative pluralization rules concurrently in both the receptive and productive modalities of language. Receptive training established correct pointing to either one or a pair of objects, in response to a spoken singular or plural label of the object(s); productive training established correct spoken labels of one or a pair of objects presented visually. However, these pluralization rules were established in each modality only for a specific class of plurals: those ending in -s for one modality, those ending in -es for the other modality. This training was successful in establishing generative, or rule-governed behaviors, such that untrained examples of singulars and plurals were usually responded to correctly. Nevertheless, despite this concurrent, generative behavior, probes revealed little generalization between modalities: three of four subjects did not generalize clearly from receptive training with one class of plurals to correct productive use of that class, nor did they generalize from productive training of the other class of plurals to correct receptive response to that class. The fourth subject, however, did show strong generalization of both these types. It was concluded that automatic generalization between receptive and productive language is not necessarily an inevitable result of language training in such subjects, and therefore may require explicit, if temporary, programming, such as by direct reinforcement.     

Inflectional morphology in German Williams syndrome

In a recent paper, Clahsen and Almazan (1998) reported a dissociation between unimpaired regular and impaired irregular past tense morphology in English Williams syndrome (WS). Our aim is to investigate whether these findings carry over to another language with different morphological systems. We present data on regular and irregular participles and noun plurals from 2 German WS subjects and 10 controls matching in mental age. For noun plurals, regular morphology is intact in WS, whereas irregular forms are impaired. A similar dissociation is observed for participles: while regular inflection is unimpaired, WS subjects, unlike controls, apply the regular suffix incorrectly to frequent irregular verbs. We discuss our findings against the current debate between connectionist and dualistic approaches to the language faculty.     

Morphological priming in the German mental lexicon.

We present results from cross-modal priming experiments on German participles and noun plurals. The experiments produced parallel results for both inflectional systems. Regular inflection exhibits full priming whereas irregularly inflected word forms show only partial priming: after hearing regularly inflected words (-t participles and -s plurals), lexical decision times on morphologically related word forms (presented visually) were similar to reaction times for a base-line condition in which prime and target were identical, but significantly shorter than in a control condition where prime and target were unrelated. In contrast, prior presentation of irregular words (-n participles and -er plurals) led to significantly longer response times on morphologically related word forms than the prior presentation of the target itself. Hence, there are clear priming differences between regularly and irregularly inflected German words. We compare the findings on German with experimental results on regular and irregular inflection in English and Italian, and discuss theoretical implications for single versus dual-mechanism models of inflection.     

The time-course of morphological constraints: evidence from eye-movements during reading

Lexical compounds in English are constrained in that the non-head noun can be an irregular but not a regular plural (e.g. mice eater vs. *rats eater), a contrast that has been argued to derive from a morphological constraint on modifiers inside compounds. In addition, bare nouns are preferred over plural forms inside compounds (e.g. mouse eater vs. mice eater), a contrast that has been ascribed to the semantics of compounds. Measuring eye-movements during reading, this study examined how morphological and semantic information become available over time during the processing of a compound. We found that the morphological constraint affected both early and late eye-movement measures, whereas the semantic constraint for singular non-heads only affected late measures of processing. These results indicate that morphological information becomes available earlier than semantic information during the processing of compounds.     

Compounding is not contingent on level-ordering in acquisition

A popular explanation of children’s avoidance of regular plurals in non-head position of compounds has been that level-ordering is in place at the beginning of children’s acquisition of compounding [Cognition 21 (1985) 73]. If this is true, then bilingualism should not make a difference. This study tested this possibility by comparing production of novel compound nouns in 25 monolingual English and 25 French-English bilingual children between the ages of 3 and 4 years. Bilingual children allowed regular plurals in non-head position significantly more often than monolinguals. This finding suggests that children can acquire compounding before learning to avoid plurals inside compounds. In discussing this finding, some reasons to doubt the existence of level-ordering are raised and possible alternatives are discussed.     

Processing and Representation of German -n Plurals: A Dual Mechanism Approach

Four subclasses of German noun plurals affixed with -n, exhibiting different degrees of predictability, are investigated in a lexical decision experiment with visual stimuli and in a cross-modal priming experiment. The lexical decision experiment compared -n plurals and irregular -er plurals to plurals with the default affix -s. Whereas the -s plurals yielded no word-form frequency effects, such effects could be observed for all other plural forms, including all subclasses of -n plurals. The priming experiment produced a different pattern. We found that the prior presentations of fully predictable -n plurals prime the stems as effectively as the stem itself, whereas -n plurals with limited predictability yielded only reduced priming effects toward their stems. These results are explained in terms of an extended dual mechanism approach, taking into account an access level and a central level of lexical processing.     

Processing of English inflectional morphology

The present paper explores the representation of inflectional morphology in the English lexicon. There has been a long-standing debate about how these inflectional relationships might be involved during on-line processing. Inflected forms may be derived from an uninflected base form by rule application; by contrast, both regular and irregular inflection may be treated in the same way, with morphological patterns emerging from mappings between base and inflected forms. The present series of experiments investigated these issues using a lexical decision task. The first experiment showed that response latencies to nouns were significantly shorter than those to verbs. A possible explanation for these results can be found in differences in inflectional structure between English nouns and verbs. Namely, the relative frequency of uninflected compared with inflected forms is greater for nouns than for verbs. Two additional experiments compared noun stimuli with different inflectional structures. In all cases, differences in response latencies were predicted by the frequency of the surface form, whether uninflected or inflected. The pattern of results lends support for a unitary associative system for processing regular inflection of nouns in English and argues against the view that regular inflected plurals are derived by rule from a single, uninflected lexical entry.     

Lexical Representation and Processing of Morphologically Complex Words: Evidence from the Reading Performance of an Italian Agrammatic Patient

The study of patients with acquired language disorders has provided crucial evidence for contemporary theories on mental lexical representation. This is particularly true for the representation of morphologically complex words. In this paper we analyzed the performance of a patient (M.B.) affected by agrammatism and dyslexia. M.B. was required to read aloud simple and morphologically complex words. The patient's pattern of errors was interpreted as the result of a predominant use of the lexical routine (phonological dyslexia). Three reading tasks were developed which allowed us to test M.B.'s ability to read morphologically complex words (reading of regular and irregular plurals; reading of high- and low-frequency singular and plural nouns; reading of evaluative suffixes). Errors were determined by frequency effect rather than by type of suffix (i.e., inflectional or derivational). High-frequency morphologically complex items seemed to meet stored representations, thus avoiding the parsing procedures that are required for less frequent items. These results are in keeping with dual route models of lexical representation of morphologically complex words.