169 research outputs found
GECTurk: Grammatical Error Correction and Detection Dataset for Turkish
Grammatical Error Detection and Correction (GEC) tools have proven useful for
native speakers and second language learners. Developing such tools requires a
large amount of parallel, annotated data, which is unavailable for most
languages. Synthetic data generation is a common practice to overcome the
scarcity of such data. However, it is not straightforward for morphologically
rich languages like Turkish due to complex writing rules that require
phonological, morphological, and syntactic information. In this work, we
present a flexible and extensible synthetic data generation pipeline for
Turkish covering more than 20 expert-curated grammar and spelling rules
(a.k.a., writing rules) implemented through complex transformation functions.
Using this pipeline, we derive 130,000 high-quality parallel sentences from
professionally edited articles. Additionally, we create a more realistic test
set by manually annotating a set of movie reviews. We implement three baselines
formulating the task as i) neural machine translation, ii) sequence tagging,
and iii) prefix tuning with a pretrained decoder-only model, achieving strong
results. Furthermore, we perform exhaustive experiments on out-of-domain
datasets to gain insights on the transferability and robustness of the proposed
approaches. Our results suggest that our corpus, GECTurk, is high-quality and
allows knowledge transfer for the out-of-domain setting. To encourage further
research on Turkish GEC, we release our datasets, baseline models, and the
synthetic data generation pipeline at https://github.com/GGLAB-KU/gecturk.Comment: Accepted at Findings of IJCNLP-AACL 202
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Sentiment Analysis for the Low-Resourced Latinised Arabic "Arabizi"
The expansion of digital communication mediums from private mobile messaging into the public through social media presented an opportunity for the data science research and industry to mine the generated big data for artificial information extraction. A popular information extraction task is sentiment analysis, which aims at extracting polarity opinions, positive, negative, or neutral, from the written natural language. This science helped organisations better understand the public’s opinion towards events, news, public figures, and products.
However, sentiment analysis has advanced for the English language ahead of Arabic. While sentiment analysis for Arabic is developing in the literature of Natural Language Processing (NLP), a popular variety of Arabic, Arabizi, has been overlooked for sentiment analysis advancements.
Arabizi is an informal transcription of the spoken dialectal Arabic in Latin script used for social texting. It is known to be common among the Arab youth, yet it is overlooked in efforts on Arabic sentiment analysis for its linguistic complexities.
As to Arabic, Arabizi is rich in inflectional morphology, but also codeswitched with English or French, and distinctively transcribed without adhering to a standard orthography. The rich morphology, inconsistent orthography, and codeswitching challenges are compounded together to have a multiplied effect on the lexical sparsity of the language, where each Arabizi word becomes eligible to be spelled in many ways, that, in addition to the mixing of other languages within the same textual context. The resulting high degree of lexical sparsity defies the very basics of sentiment analysis, classification of positive and negative words. Arabizi is even faced with a severe shortage of data resources that are required to set out any sentiment analysis approach.
In this thesis, we tackle this gap by conducting research on sentiment analysis for Arabizi. We addressed the sparsity challenge by harvesting Arabizi data from multi-lingual social media text using deep learning to build Arabizi resources for sentiment analysis. We developed six new morphologically and orthographically rich Arabizi sentiment lexicons and set the baseline for Arabizi sentiment analysis on social media
Open-source resources and standards for Arabic word structure analysis: Fine grained morphological analysis of Arabic text corpora
Morphological analyzers are preprocessors for text analysis. Many Text Analytics applications need them to perform their tasks. The aim of this thesis is to develop
standards, tools and resources that widen the scope of Arabic word structure analysis - particularly morphological analysis, to process Arabic text corpora of different domains, formats and genres, of both vowelized and non-vowelized text.
We want to morphologically tag our Arabic Corpus, but evaluation of existing morphological analyzers has highlighted shortcomings and shown that more research is
required. Tag-assignment is significantly more complex for Arabic than for many languages. The morphological analyzer should add the appropriate linguistic information
to each part or morpheme of the word (proclitic, prefix, stem, suffix and enclitic); in effect, instead of a tag for a word, we need a subtag for each part.
Very fine-grained distinctions may cause problems for automatic morphosyntactic analysis – particularly probabilistic taggers which require training data, if some words can change grammatical tag depending on function and context; on the other hand, finegrained distinctions may actually help to disambiguate other words in the local context. The SALMA – Tagger is a fine grained morphological analyzer which is mainly depends on linguistic information extracted from traditional Arabic grammar books and prior knowledge broad-coverage lexical resources; the SALMA – ABCLexicon.
More fine-grained tag sets may be more appropriate for some tasks. The SALMA –Tag Set is a theory standard for encoding, which captures long-established traditional
fine-grained morphological features of Arabic, in a notation format intended to be compact yet transparent.
The SALMA – Tagger has been used to lemmatize the 176-million words Arabic Internet Corpus. It has been proposed as a language-engineering toolkit for Arabic lexicography and for phonetically annotating the Qur’an by syllable and primary stress information, as well as, fine-grained morphological tagging
Cappadocian kinship
Cappadocian kinship systems are very interesting from a sociolinguistic and anthropological perspective because of the mixture of inherited Greek and borrowed Turkish kinship terms. Precisely because the number of Turkish kinship terms differs from one variety to another, it is necessary to talk about Cappadocian kinship systems in the plural rather than about the Cappadocian kinship system in the singular. Although reference will be made to other Cappadocian varieties, this paper will focus on the kinship systems of Mišotika and Aksenitika, the two Central Cappadocian dialects still spoken today in several communities in Greece. Particular attention will be given to the use of borrowed Turkish kinship terms, which sometimes seem to co-exist together with their inherited Greek counterparts, e.g. mána vs. néne ‘mother’, ailfó/aelfó vs. γardáš ‘brother’ etc. In the final part of the paper some kinship terms with obscure or hitherto unknown etymology will be discussed, e.g. káka ‘grandmother’, ižá ‘aunt’, lúva ‘uncle (father’s brother)’ etc
A study of the translation of sentiment in user-generated text
A thesis submitted in partial ful filment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Emotions are biological states of feeling that humans may verbally express to
communicate their negative or positive mood, influence others, or even afflict
harm. Although emotions such as anger, happiness, affection, or fear are
supposedly universal experiences, the lingual realisation of the emotional
experience may vary in subtle ways across different languages. For this reason,
preserving the original sentiment of the source text has always been a challenging
task that draws in a translator's competence and fi nesse. In the professional
translation industry, an incorrect translation of the sentiment-carrying lexicon is
considered a critical error as it can be either misleading or in some cases harmful
since it misses the fundamental aspect of the source text, i.e. the author's
sentiment.
Since the advent of Neural Machine Translation (NMT), there has been a
tremendous improvement in the quality of automatic translation. This has lead to
an extensive use of NMT online tools to translate User-Generated Text (UGT)
such as reviews, tweets, and social media posts, where the main message is often
the author's positive or negative attitude towards an entity. In such scenarios, the
process of translating the user's sentiment is entirely automatic with no human
intervention, neither for post-editing nor for accuracy checking. However, NMT
output still lacks accuracy in some low-resource languages and sometimes makes
critical translation errors that may not only distort the sentiment but at times flips
the polarity of the source text to its exact opposite.
In this thesis, we tackle the translation of sentiment in UGT by NMT systems from two perspectives: analytical and experimental. First, the analytical approach
introduces a list of linguistic features that can lead to a mistranslation of
ne-grained emotions between different language pairs in the UGT domain. It also
presents an error-typology specifi c to Arabic UGT illustrating the main linguistic
phenomena that can cause mistranslation of sentiment polarity when translating
Arabic UGT into English by NMT systems. Second, the experimental approach
attempts to improve the translation of sentiment by addressing some of the
linguistic challenges identifi ed in the analysis as causing mistranslation of
sentiment both on the word-level and on the sentence-level. On the word-level, we
propose a Transformer NMT model trained on a sentiment-oriented vector space
model (VSM) of UGT data that is capable of translating the correct sentiment
polarity of challenging contronyms. On the sentence-level, we propose a
semi-supervised approach to overcome the problem of translating sentiment
expressed by dialectical language in UGT data. We take the translation of
dialectical Arabic UGT into English as a case study. Our semi-supervised AR-EN
NMT model shows improved performance over the online MT Twitter tool in
translating dialectical Arabic UGT not only in terms of translation quality but
also in the preservation of the sentiment polarity of the source text. The
experimental section also presents an empirical method to quantify the notion of
sentiment transfer by an MT system and, more concretely, to modify automatic
metrics such that its MT ranking comes closer to a human judgement of a poor or
good translation of sentiment
Lexical selection for machine translation
Current research in Natural Language Processing (NLP) tends to exploit corpus resources as a way of overcoming the problem of knowledge acquisition. Statistical analysis of corpora can reveal trends and probabilities of occurrence, which have proved to be helpful in various ways. Machine Translation (MT) is no exception to this trend. Many MT researchers have attempted to extract knowledge from parallel bilingual corpora. The MT problem is generally decomposed into two sub-problems: lexical selection and reordering of the selected words. This research addresses the problem of lexical selection of open-class lexical items in the framework of MT. The work reported in this thesis investigates different methodologies to handle this problem, using a corpus-based approach. The current framework can be applied to any language pair, but we focus on Arabic and English. This is because Arabic words are hugely ambiguous and thus pose a challenge for the current task of lexical selection. We use a challenging Arabic-English parallel corpus, containing many long passages with no punctuation marks to denote sentence boundaries. This points to the robustness of the adopted approach. In our attempt to extract lexical equivalents from the parallel corpus we focus on the co-occurrence relations between words. The current framework adopts a lexicon-free approach towards the selection of lexical equivalents. This has the double advantage of investigating the effectiveness of different techniques without being distracted by the properties of the lexicon and at the same time saving much time and effort, since constructing a lexicon is time-consuming and labour-intensive. Thus, we use as little, if any, hand-coded information as possible. The accuracy score could be improved by adding hand-coded information. The point of the work reported here is to see how well one can do without any such manual intervention. With this goal in mind, we carry out a number of preprocessing steps in our framework. First, we build a lexicon-free Part-of-Speech (POS) tagger for Arabic. This POS tagger uses a combination of rule-based, transformation-based learning (TBL) and probabilistic techniques. Similarly, we use a lexicon-free POS tagger for English. We use the two POS taggers to tag the bi-texts. Second, we develop lexicon-free shallow parsers for Arabic and English. The two parsers are then used to label the parallel corpus with dependency relations (DRs) for some critical constructions. Third, we develop stemmers for Arabic and English, adopting the same knowledge -free approach. These preprocessing steps pave the way for the main system (or proposer) whose task is to extract translational equivalents from the parallel corpus. The framework starts with automatically extracting a bilingual lexicon using unsupervised statistical techniques which exploit the notion of co-occurrence patterns in the parallel corpus. We then choose the target word that has the highest frequency of occurrence from among a number of translational candidates in the extracted lexicon in order to aid the selection of the contextually correct translational equivalent. These experiments are carried out on either raw or POS-tagged texts. Having labelled the bi-texts with DRs, we use them to extract a number of translation seeds to start a number of bootstrapping techniques to improve the proposer. These seeds are used as anchor points to resegment the parallel corpus and start the selection process once again. The final F-score for the selection process is 0.701. We have also written an algorithm for detecting ambiguous words in a translation lexicon and obtained a precision score of 0.89.EThOS - Electronic Theses Online ServiceEgyptian GovernmentGBUnited Kingdo
Text Normalisation of Dialectal Finnish
Tekstin normalisointi on prosessi, jossa epästandardia kirjoitettua kieltä muutetaan standardisoituun muotoon. Murteet ovat yksi esimerkki epästandardista kielestä, joka voi poiketa huomattavastikin standardisoidusta yleiskielestä. Lisäksi suomen kieli on ortografialtaan varsin pitkälti foneemista, minkä ansiosta myös puhutun kielen ominaispiirteet on mahdollista tuoda esille kirjoitetussa muodossa. Etenkin epävirallisilla alustoilla ja arkikielisessä kontekstissa, kuten sosiaalisessa mediassa, suomen kielen puhujat saattavat kirjoittaa sanat kuten ääntäisivät ne normaalisti puhuessaan. Tällaista epästandardista kielestä koostuvaa aineistoa voi löytää myös luonnollisen kielen käsittelyn tarpeisiin esimerkiksi Twitteristä. Perinteiselle yleiskieliselle tekstiaineistolle suunnatut luonnollisen kielen käsittelyn työkalut eivät kuitenkaan välttämättä saavuta toivottavia tuloksia puhekieliselle aineistolle sovellettuna, jolloin ratkaisuna voidaan käyttää välivaiheena tekstin normalisointia. Normalisointiprosessissa syötteenä käytettävä puhekielinen tai muutoin epästandardia kieltä sisältävä teksti muutetaan standardisoituun kirjoitusasuun, jota luonnollisen kielen käsittelyn työkalut paremmin ymmärtävät.
Tämä työ pohjaa aiempaan tutkimukseen, jota on tehty suomen murteiden normalisoinnin parissa. Aiemmissa tutkimuksissa on todettu, että merkkipohjaiset BRNN-neuroverkkomallit (Bidirectional Recurrent Neural Nerwork) saavuttavat hyviä tuloksia suomen kielen murteiden normalisoinnissa, kun syötteenä käytetään sanoja kolmen kappaleen lohkoissa. Tämä tarkoittaa, että järjestelmä saa syötteenä kerrallaan kolmen sanan joukon, ja jokainen sana on edelleen pilkottu välilyönnein eroteltuihin kirjoitusmerkkeihin. Tässä työssä pyrittiin käyttämään samoja metodeja ja aineistoa kuin aiemmassa tutkimuksessa, jotta tulokset olisivat vertailukelpoisia. Aineistona on käytetty Kotimaisten kielten keskuksen ylläpitämää Suomen kielen näytteitä -korpusta, ja normalisointiin on käytetty OpenNMT-nimistä avoimen lähdekoodin kirjastoa. Työssä toteutetuista kokeiluista saadut tulokset näyttävät vahvistavan aiempien tutkimustulosten pohjalta tehdyt löydökset, mutta lisäksi on viitteitä siitä, että neuroverkkomallit saattaisivat pidemmistä lohkoista koostuvista syötteistä. BRNN-mallin lisäksi työssä kokeillaan myös muita neuroverkkoarkkitehtuureja, mutta vertailtaessa sanavirheiden suhdelukua mittaavaa WER-arvoa (Word Error Rate) voidaan todeta, että BRNN-malli suoriutuu normalisointitehtävästä muita neuroverkkoarkkitehtuureja paremmin
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