This paper describes in details the first version of Morphonette, a new French morphological resource and a new radically lexeme-based method of morphological analysis. This research is grounded in a paradigmatic conception of derivational morphology where the morphological structure is a structure of the entire lexicon and not one of the individual words it contains. The discovery of this structure relies on a measure of morphological similarity between words, on formal analogy and on the properties of two morphological paradigms:
The construction of Morphonette uses a bootstrapping algorithm in order to extend an initial reliable seed. This technique has often also been used in computational morphology, for instance by @cite_19 or by @cite_13 . However, our method differs from these ones because it is fully lexeme-based and does not make use of morpheme nor contain any representation of them. Morphological regularities emerge from a very large set of analogies. Gathering of this set is one of contributions of the work presented in this paper. It was made possible through the use of the measure of morphological similarity of @cite_10 . This measure was inspired by work on small words by @cite_11 . Our method is also close to the ones of @cite_16 and @cite_3 where the words are not decomposed into morphemes. Both make use of string edit distance to identify formal similarity between words. Our work is also close to the one by @cite_9 , @cite_4 and @cite_0 who use formal analogies to analyze words morphologically and to translate them.
@cite_4 @cite_10 @cite_9 @cite_3 @cite_0 @cite_19 @cite_16 @cite_13 @cite_11
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The paper presents a computational model aiming at making the morphological structure of the lexicon emerge from the formal and semantic regularities of the words it contains. The model is purely lexeme-based. The proposed morphological structure consists of (1) binary relations that connect each headword with words that are morphologically related, and especially with the members of its morphological family and its derivational series, and of (2) the analogies that hold between the words. The model has been tested on the lexicon of French using the TLFi machine readable dictionary. This paper describes a system and set of algorithms for automatically inducing stand-alone monolingual part-of-speech taggers, base noun-phrase bracketers, named-entity taggers and morphological analyzers for an arbitrary foreign language. Case studies include French, Chinese, Czech and Spanish.Existing text analysis tools for English are applied to bilingual text corpora and their output projected onto the second language via statistically derived word alignments. Simple direct annotation projection is quite noisy, however, even with optimal alignments. Thus this paper presents noise-robust tagger, bracketer and lemmatizer training procedures capable of accurate system bootstrapping from noisy and incomplete initial projections.Performance of the induced stand-alone part-of-speech tagger applied to French achieves 96 core part-of-speech (POS) tag accuracy, and the corresponding induced noun-phrase bracketer exceeds 91 F-measure. The induced morphological analyzer achieves over 99 lemmatization accuracy on the complete French verbal system.This achievement is particularly noteworthy in that it required absolutely no hand-annotated training data in the given language, and virtually no language-specific knowledge or resources beyond raw text. Performance also significantly exceeds that obtained by direct annotation projection. Electronic dictionaries offer many possibilities unavailable in paper dictionaries to view, display or access information. However, even these resources fall short when it comes to access words sharing semantic features and certain aspects of form: few applications offer the possibility to access a word via a morphologically or semantically related word. In this paper, we present such an application, POLYMOTS, a lexical database for contemporary French containing 20.000 words grouped in 2.000 families. The purpose of this resource is to group words into families on the basis of shared morpho-phonological and semantic information. Words with a common stem form a family; words in a family also share a set of common conceptual fragments (in some families there is a continuity of meaning, in others meaning is distributed). With this approach, we capitalize on the bidirectional link between semantics and morpho-phonology : the user can thus access words not only on the basis of ideas, but also on the basis of formal characteristics of the word, i.e. its morphological features. The resulting lexical database should help people learn French vocabulary and assist them to find words they are looking for, going thus beyond other existing lexical resources. While most approaches to unsupervised morphology acquisition often rely on metrics based on information theory for identifying morphemes, we describe a novel approach relying on the notion of formal analogy, that is, a relation between four forms, such as: reader is to doer as reading is to doing. Our assumption is that formal analogies identify pairs of morphologically related words, for instance reader reading and doer doing. Based on this assumption, our approach simply consists in identifying all the formal analogies involving the words in a lexicon. It turned out that for large lexicons, this happens to be a very time consuming task. Therefore, we report our attempts in designing practical systems based on the analogical principle. We applied our systems on the five languages of the shared task. The learning is made in an unsupervised manner, making use of the supplied lexicons only.