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.     

Representation of grammatical properties of Italian verbs in the mental lexicon

The present study focuses on the representation of verbs in the Italian mental lexicon and investigates some grammatical properties: inflectional class, mood, tense, and person. Two experiments based on free recall of single inflected forms are reported. The patterns of recall and error are taken as evidence for the grammatical and morphological information exploited in the access to the verb forms. The pattern of results provides support for the hypothesis that in the mental lexicon the information about conjugation and mood is an organizational criterion for the representation of verbal forms. An interaction between mood and conjugation, likely to arise from the difference in productivity between conjugations, is also observed.     

Rules versus statistics: insights from a highly inflected language

Inflectional morphology has been taken as a paradigmatic example of rule-governed grammatical knowledge (Pinker, 1999). The plausibility of this claim may be related to the fact that it is mainly based on studies of English, which has a very simple inflectional system. We examined the representation of inflectional morphology in Serbian, which encodes number, gender, and case for nouns. Linguists standardly characterize this system as a complex set of rules, with disagreements about their exact form. We present analyses of a large corpus of nouns which showed that, as in English, Serbian inflectional morphology is quasiregular: It exhibits numerous partial regularities creating neighborhoods that vary in size and consistency. We then asked whether a simple connectionist network could encode this statistical information in a manner that also supported generalization. A network trained on 3,244 Serbian nouns learned to produce correctly inflected phonological forms from a specification of a word's lemma, gender, number, and case, and generalized to untrained cases. The model's performance was sensitive to variables that also influence human performance, including surface and lemma frequency. It was also influenced by inflectional neighborhood size, a novel measure of the consistency of meaning to form mapping. A word-naming experiment with native Serbian speakers showed that this measure also affects human performance. The results suggest that, as in English, generating correctly inflected forms involves satisfying a small number of simultaneous probabilistic constraints relating form and meaning. Thus, common computational mechanisms may govern the representation and use of inflectional information across typologically diverse languages.     

In search of meaning: Semantic effects on past-tense inflection

Within single-mechanism connectionist models of inflectional morphology, generating the past-tense form of a verb depends upon the interaction of semantic and phonological representations, with semantic information being particularly important for irregular or exception verbs. We assessed this hypothesis in two experiments requiring normal speakers to produce the past tense from a verb stem that takes a regular or exceptional past tense. Experiment 1 revealed significant latency advantages for high- over low-imageability words for both regular verbs (e.g., “lunged” faster than “loved”) and exception items (e.g., “drank” faster than “dealt”); but critically, this effect was significantly larger for exceptions than for regulars. Experiment 2 employed a semantic priming paradigm where participants inflected verb stems (e.g., sit) preceded by related (e.g., chair) or unrelated primes (e.g., jug) and revealed a priming effect in accuracy that was confined to the exception items. Our results are consistent with predictions from single-mechanism connectionist models of inflectional morphology and converge with findings from neurological patients and studies of reading aloud.     

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.     

Putting the bits together: an information theoretical perspective on morphological processing

In this study we introduce an information-theoretical formulation of the emergence of type- and token-based effects in morphological processing. We describe a probabilistic measure of the informational complexity of a word, its information residual, which encompasses the combined influences of the amount of information contained by the target word and the amount of information carried by its nested morphological paradigms. By means of re-analyses of previously published data on Dutch words we show that the information residual outperforms the combination of traditional token- and type-based counts in predicting response latencies in visual lexical decision, and at the same time provides a parsimonious account of inflectional, derivational, and compounding processes.     

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.     

Neurocognitive dimensions of lexical complexity in Polish

Neuroimaging studies of English suggest that speech comprehension engages two interdependent systems: a bilateral fronto-temporal network responsible for general perceptual and cognitive processing, and a specialised left-lateralised network supporting specifically linguistic processing. Using fMRI we test this hypothesis in Polish, a Slavic language with rich and diverse morphology. We manipulated general perceptual complexity (presence or absence of an onset-embedded stem, e.g. kotlet ‘cutlet’ vs. kot ‘cat’) and specifically linguistic complexity (presence of an inflectional affix, e.g. dom ‘house, Nom’ vs. dom-u ‘house, Gen’). Non-linguistic complexity activated a bilateral network, as in English, but we found no differences between inflected and uninflected nouns. Instead, all types of words activated left inferior frontal areas, suggesting that all Polish words can be considered linguistically ‘complex’ in processing terms. The results support a dual network hypothesis, but highlight differences between languages like English and Polish, and underline the importance of cross-linguistic comparisons.     

Can word formation be understood or understanded by semantics alone?

Arguments concerning the relative role of semantic and grammatical factors in word formation have proven to be a wedge issue in current debates over the nature of linguistic representation and processing. In the present paper, we re-examine claims by Ramscar [Ramscar, M. (2002). The role of meaning in inflection: Why the past tense does not require a rule. Cognitive Psychology, 45, 45-94.] that it is semantic rather than grammatical factors that influence the choice of regular or irregular past tense forms for English verbs. In Experiment 1, we first replicated Ramscar's (2002) experiment, which showed semantic influences on choice of past tense inflection. A novel verb, splink, was introduced in a semantic context that was reminiscent of an existing regular or irregular rhyme verb: blink or drink. Participants favored the past tense form (splinked or splank) that matched that of the semantically similar verb. In Experiment 2, we introduced novel verbs in a context suggesting that they were grammatically derived from nouns (i.e., denominals). Some current symbolic processing models propose that regular past tense forms should be preferred for such forms. When Ramscar's (2002) original contexts for derivational verbs were re-tested in this condition, we replicated his failure to find a preference for regular past tense forms. However, when the contexts were modified to make the grammatical process more salient, we did find a preference for regular past tense forms, suggesting that the derivational status might have been ambiguous in the original materials. In Experiment 3, we tested whether acceptability ratings for regular or irregular past tense forms of grammatically derived verbs could be explained by semantic distance metrics or by ratings of noun-to-verb derivational status. Ratings of semantic distance and grammatical derivation were orthogonal factors in Experiment 3. Only derivational status predicted acceptability ratings for regular past tense forms. Taken together, the present results suggest that semantic factors do not explain the regularization of irregular verbs in derivational contexts, although semantic factors can affect the choice of past tense forms in certain circumstances.     

Dutch plural inflection: the exception that proves the analogy

We develop the view that inflection is driven partly by non-phonological analogy and that non-phonological information is of particular importance to the inflection of non-canonical roots, which in the view of [Marcus, G. F., Brinkmann, U., Clahsen, H., Wiese, R., & Pinker, S. (1995). German inflection: the exception that proves the rule. Cognitive Psychology, 29, 189-256.] are inflected by a symbolic rule process. We used the Dutch plural to evaluate these claims. An analysis of corpus data shows that a model using non-phonological information (orthography) produces significantly fewer errors on plurals of non-canonical Dutch nouns, in particular borrowings, than a model that includes only phonological information. Moreover, we show that a double default system, as proposed by Pinker [Pinker, S. (1999). Words and rules. London: Phoenix.], does not offer an advantage over the latter model. A second study, examining the use of orthography in an online plural production task, shows that, in Dutch, the chosen pseudoword plural is significantly affected by non-phonological information. A final simulation study confirms that these results are in line with a model of inflectional morphology that explains the inflection of non-canonical roots by non-phonological analogy instead of by a default rule process.