Claudia Marzi

Word alignment and paradigm induction

The variety of morphological processes attested in and combinations thereof pose severe problems to unsupervised algorithms of morphology induction. The paper analyses morphological strategies for word recoding. Our model endorses the hypothesis that lexical forms are memorised as full units. At the same time, lexical units are paradigmatically organised. We show that the overall amount of redundant morphological structure emerging from paradigm-based self-organisation has a clear impact on generalisation. This supports the view that issues of word representation and issues of word processing are .

Morphological structure through lexical parsability

The emergence of morphological structure in lexical acquisi- tion is analysed in the computational framework of Temporal Self-Organ- ising Maps (TSOMs), to provide an explanatory basis for both psycholin- guistic and linguistic accounts of lexical parsability. The investigation we propose is grounded on the hypothesis that perception of morphological structure (parsability) and frequency strongly correlate in the acquisition of inflectional paradigms. Analysis of experimental results of word acqui - sition obtained by artificially varying training conditions, allows us to un - derstand developmental competition between fully-inflected word forms, and to investigate a hierarchy of frequency effects. The computational and theoretical implications of such a memory-based view of the relation- ship between frequency and perception, and its potential to account for long-term morphological effects in lexical acquisition are illustrated.

ADAPTIVE STRATEGIES IN LEXICAL ACQUISITION

The emergence of morphological patterns from lexical storage in language acquisition is conditioned by language-specific factors as well as extra-linguistic cognitive capacities. With particular reference to the acquisition of plural markers in German, in a memory-based perspective highlighting interesting theoretical implications for usage-based models, the paper analyses acquisitional strategies by focussing on emergent rela- tions between stored word forms and on dynamic expectation/competition of incoming input. In particular, we outline an adaptive multifactorial ac- count of morphological processing that includes both frequency and for- mal factors. Our investigation is supported by a computational model of morphology acquisition/processing based on self-organisation memories, where word representations are dynamically recoded as time-series.

Word knowledge and word usage: a foreword

This paper attempts to demarcate the class of Akan verb-noun compounds like bɔ-adeɛ [create-thing] ‘creator’, to discuss their properties and to present a Construction Morphology account of the properties. Working with the view that Akan verbs are invariably consonant initial and that the verb constituent of verb-noun compounds are invariably simplex, it is shown that many exemplars cited in the Akan literature do not belong to the class because they bear affixes that betray them as either nominalized verb phrases or noun-noun compounds with deverbal left-hand constituents. It is shown that the noun constituent may be the internal argument of the verb mostly, but may also be the external argument or an adjunct, usually naming the location of the action. The noun constituent may bear the semantic role of undergoer, affected object, patient, instrument, location, result or goal of the action/event designated by the verb, while the denotatum of the compound may be agent, theme, instrument, location or condition. Finally, it is shown that Akan verb-noun compounds have endocentric and exocentric subtypes whose properties are adequately accounted for in Construction Morphology.*

Word processing for Arabic language: A reappraisal of morphology induction through adaptive memory self-organisation strategies

Modelling the mental lexicon focuses on processing and storage dynamics, since lexical organisation relies on the process of input recoding and adaptive strategies for long-term memory organisation. A fundamental issue in word processing is represented by the emergence of the morphological organisation level in the lexicon, based on paradigmatic relations between fully-stored word forms. Morphology induction can be defined as the task of identifying morphological formatives within morphologically complex word forms. In the computational framework we propose here (TSOMs), based on Self-Organising Maps with Hebbian connections defined over a temporal layer, the identification/perception of surface morphological relations involves the alignment of recoded representations of morphologically-related input words. Facing a non-concatenative morphology such as the Arabic inflectional system prompts a reappraisal of morphology induction through adaptive organisation strategies, which affect both lexical representations and long-term storage. We will show how a strongly adaptive self-organisation during training is conducive to emergent relations between stored word forms, and to high accuracy rates in generalising knowledge of stored words to unknown forms.

Computational Linguistics and Language Physiology: Insights from Arabic NLP and Cooperative Editing

Computer processing of written Arabic raises a number of challenges to traditional parsing architectures on many levels of linguistic analysis. In this contribution, we review some of these core issues and the demands they make, to suggest different strategies to successfully tackle them. In the end, we assess these issues in connection with the behaviour of neuro-biologically inspired lexical architectures known as Temporal Self-Organising Maps. We show that, far from being language-specific problems, issues in Arabic processing can shed light on some fundamental characteristics of the human language processor, such as structure-based lexical recoding, concurrent, competitive activation of output candidates and dynamic selection of optimal solutions.