Composition studies lacks a comprehensive theory of error, one which successfully defines error in writing and offers a pedagogical response to ostensible errors that neither ignores nor pathologizes them. Electronic text-critiquing technologies offer some promise of helping writers notice and correct errors, but they are under-researched in composition and rarely well-integrated into pedagogical praxis. This research on the grammar and style checker in Microsoft Word considers the program as an electronic checklist for making decisions about what counts as an error in a given rhetorical situation. This study also offers a theory of error grounded in the idea of attention, or cognitive load, some of which an electronic checker can relieve in its areas of its greatest effectiveness, which this research quantifies. The proposed theory of error forms the basis for a pedagogy of register, understood as typified style, and establishes that error itself can be a strategic style move.

O CoGrOO é um corretor gramatical de código aberto em uso por milhares de usuários de uma popular suíte de escritório de código aberto. Ele é capaz de identificar erros como: colocação pronominal, concordância nominal, concordância sujeito-verbo, uso da crase, concordância nominal e verbal e outros erros comuns de escrita em Português do Brasil. Para tal, o CoGrOO realiza uma análise híbrida: inicialmente o texto é anotado usando técnicas estatísticas de Processamento de Linguagens Naturais e, em seguida, um sistema baseado em regras é responsável por identificar os possíveis erros gramaticais. O objetivo deste trabalho é reduzir a quantidade de omissões e intervenções indevidas e, ao mesmo tempo, aumentar a quantidade de verdadeiros positivos sem, entretanto, adicionar novas regras de detecção de erros. A última avaliação científica do corretor gramatical foi realizada em 2006 e, desde então, não foram realizados estudos detalhados quanto ao seu desempenho, apesar de o código do sistema ter passado por substancial evolução. Este trabalho contribuirá com uma detalhada avaliação dos anotadores estatísticos e os resultados serão comparados com o estado da arte. Uma vez que os anotadores do CoGrOO estão disponíveis como software livre, melhorias nesses módulos gerarão boas alternativas a sistemas proprietários. / CoGrOO is an open source Brazilian Portuguese grammar checker currently used by thousands of users of a popular open source office suite. It is capable of identifying Brazilian Portuguese mistakes such as pronoun placement, noun agreement, subject-verb agreement, usage of the accent stress marker, subject-verb agreement, and other common errors of Brazilian Portuguese writing. To accomplish this, it performs a hybrid analysis; initially it annotates the text using statistical Natural Language Processing (NLP) techniques, and then a rule-based check is performed to identify possible grammar errors. The goal of this work is to reduce omissions and false alarms while improving true positives without adding new error rules. The last rigorous evaluation of the grammar checker was done in 2006 and since then there has been no detailed study on how it has been performing. This work will also contribute a detailed evaluation of low-level NLP modules and the results will be compared to state-of-the-art results. Since the low-level NLP modules are available as open source software, improvements on their performance will make them robust, free and ready-to-use alternatives for other systems.

O CoGrOO é um corretor gramatical de código aberto em uso por milhares de usuários de uma popular suíte de escritório de código aberto. Ele é capaz de identificar erros como: colocação pronominal, concordância nominal, concordância sujeito-verbo, uso da crase, concordância nominal e verbal e outros erros comuns de escrita em Português do Brasil. Para tal, o CoGrOO realiza uma análise híbrida: inicialmente o texto é anotado usando técnicas estatísticas de Processamento de Linguagens Naturais e, em seguida, um sistema baseado em regras é responsável por identificar os possíveis erros gramaticais. O objetivo deste trabalho é reduzir a quantidade de omissões e intervenções indevidas e, ao mesmo tempo, aumentar a quantidade de verdadeiros positivos sem, entretanto, adicionar novas regras de detecção de erros. A última avaliação científica do corretor gramatical foi realizada em 2006 e, desde então, não foram realizados estudos detalhados quanto ao seu desempenho, apesar de o código do sistema ter passado por substancial evolução. Este trabalho contribuirá com uma detalhada avaliação dos anotadores estatísticos e os resultados serão comparados com o estado da arte. Uma vez que os anotadores do CoGrOO estão disponíveis como software livre, melhorias nesses módulos gerarão boas alternativas a sistemas proprietários. / CoGrOO is an open source Brazilian Portuguese grammar checker currently used by thousands of users of a popular open source office suite. It is capable of identifying Brazilian Portuguese mistakes such as pronoun placement, noun agreement, subject-verb agreement, usage of the accent stress marker, subject-verb agreement, and other common errors of Brazilian Portuguese writing. To accomplish this, it performs a hybrid analysis; initially it annotates the text using statistical Natural Language Processing (NLP) techniques, and then a rule-based check is performed to identify possible grammar errors. The goal of this work is to reduce omissions and false alarms while improving true positives without adding new error rules. The last rigorous evaluation of the grammar checker was done in 2006 and since then there has been no detailed study on how it has been performing. This work will also contribute a detailed evaluation of low-level NLP modules and the results will be compared to state-of-the-art results. Since the low-level NLP modules are available as open source software, improvements on their performance will make them robust, free and ready-to-use alternatives for other systems.

Correction of the articles in English texts is approached as an article generation task, i.e. each noun phrase is assigned with a class corresponding to the definite, indefinite or zero article. Supervised machine learning methods are used to first replicate and then improve upon the best reported result in the literature known to the author. By feature engineering and a different choice of the learning method, about 34% drop in error is achieved. The resulting model is further compared to the performance of expert annotators. Although the comparison is not straightforward due to the differences in the data, the results indicate the performance of the trained model is comparable to the human-level performance when measured on the in-domain data. On the other hand, the model does not generalize well to different types of data. Using a large-scale language model to predict an article (or no article) for each word of the text has not proved successful. 1

Στόχος της παρούσας διδακτορικής διατριβής είναι ο σχεδιασμός και η υλοποίηση ενός ηλεκτρονικού εύχρηστου εργαλείου (γραμματικού διορθωτή) που θα προβαίνει στη μορφολογική και συντακτική ανάλυση φράσεων, προτάσεων και λέξεων με σκοπό τη διόρθωση γραμματικών και υφολογικών λαθών. Βάση για την αντιμετώπιση όλων αυτών των ζητημάτων συνιστούν οι ρυθμίσεις της Γραμματικής (αναπροσαρμογή της Μικρής Νεοελληνικής Γραμματικής του Μανόλη Τριανταφυλλίδη), η οποία αποτελεί την επίσημη, από το 1976, γραμματική κωδικοποίηση της νεοελληνικής γλώσσας. (Κατά την εκπόνηση της διατριβής δεν έχουν ληφθεί υπόψη οι -ελάχιστες- διαφορές της νέας σχολικής γραμματικής Ε΄ και Στ΄ Δημοτικού). Με δεδομένη την απουσία ενός τέτοιου εργαλείου για τα ελληνικά, η ανάπτυξη του προϊόντος θα βασίζεται καταρχήν στη λεπτομερή καταγραφή, ανάλυση και τυποποίηση των λαθών του γραπτού λόγου και στη συνέχεια στην επιλογή του λογισμικού εκείνου που θα περιγράφει φορμαλιστικά τα γραμματικά λάθη. Η διατριβή παρουσιάζει στατιστικά στοιχεία που αφορούν τη σχέση των λαθών με το φύλο ή με το κειμενικό είδος των κειμένων στα οποία και συναντούνται όπως επίσης και την αναγνώρισή τους από μαθητές. Στην παρούσα έρευνα παρουσιάζεται ο φορμαλισμός υλοποίησης που χρησιμοποιήθηκε (Mnemosyne) και παρουσιάζονται οι ιδιαιτερότητες της ελληνικής γλώσσας που δυσχεραίνουν την υπολογιστική επεξεργασία της. Ο φορμαλισμός αυτός έχει ήδη χρησιμοποιηθεί για αναγνώριση πολυλεκτικών όρων καθώς και για την υλοποίηση ηλεκτρονικών εργαλείων (γραμματικών) με στόχο την αυτόματη εξαγωγή πληροφορίας. Με αυτό τον τρόπο όλοι οι χρήστες της γλώσσας (και όχι μόνο αυτοί που έχουν την ελληνική ως μητρική γλώσσα) μπορούν να κατανοήσουν καλύτερα όχι μόνον τη λειτουργία των διαφόρων μερών του συστήματος της γλώσσας αλλά και τον τρόπο με τον οποίο λειτουργούν οι μηχανισμοί λειτουργίας του γλωσσικού συστήματος κατά τη γλωσσική ανάλυση . 14 Οι βασικές περιοχές γραμματικών λαθών όπου θα παρεμβαίνει ο γραμματικός διορθωτής θα είναι: 1) θέματα τονισμού και στίξης, 2) τελικό -ν, 3) υφολογικά ζητήματα (ρηματικοί τύποι σε περιπτώσεις διπλοτυπίας, κλιτικοί τύποι), 4) ζητήματα καθιερωμένης γραφής λέξεων ή φράσεων της νέας ελληνικής γλώσσας (στερεότυπες φράσεις, λόγιοι τύποι), 5) ζητήματα κλίσης (λανθασμένοι κλιτικοί τύποι ονομάτων ή ρημάτων είτε λόγω άγνοιας είτε λόγω σύγχυσης), 6) ζητήματα λεξιλογίου (περιπτώσεις εννοιολογικής σύγχυσης, ελληνικές αποδόσεις ξένων λέξεων, πλεονασμός, χρήση εσφαλμένης φράσης ή λέξης), 7) ζητήματα ορθογραφικής σύγχυσης (ομόηχες λέξεις), 8) ζητήματα συμφωνίας (θέματα ασυμφωνίας στοιχείων της ονοματικής ή της ρηματικής φράσης), 9) ζητήματα σύνταξης (σύνταξη ρημάτων) και 10) περιπτώσεις λαθών που απαιτούν πιο εξειδικευμένη διαχείριση ορθογραφικής διόρθωσης. Βάση για την υλοποίηση του λεξικού αποτελεί το ηλεκτρονικό μορφολογικό λεξικό Neurolingo Lexicon1, ένα λεξικό χτισμένο σε ένα μοντέλο 5 επιπέδων με τουλάχιστον 90.000 λήμματα που παράγουν 1.200.000 κλιτικούς τύπους. Οι τύποι αυτοί φέρουν πληροφορία: α) ορθογραφική (ορθή γραφή του κλιτικού τύπου), β) μορφηματική (το είδος των μορφημάτων: πρόθημα, θέμα, επίθημα, κατάληξη, που απαρτίζουν τον κλιτικό τύπο), γ) μορφοσυντακτική (μέρος του λόγου, γένος, πτώση, πρόσωπο κτλ.), δ) υφολογική (τα υφολογικά χαρακτηριστικά του τύπου: προφορικό, λόγιο κτλ.) και ε) ορολογική (επιπλέον πληροφορία για το αν ο τύπος αποτελεί μέρος ειδικού λεξιλογίου). Το λεξικό αυτό αποτελεί και τον θεμέλιο λίθο για την υποστήριξη του γραμματικού διορθωτή (Grammar Checker). Η αξία και ο ρόλος του μορφολογικού λεξικού για την υποστήριξη ενός γραμματικού διορθωτή είναι αυτονόητη, καθώς η μορφολογία είναι το πρώτο επίπεδο γλώσσας που εξετάζεται και το συντακτικό επίπεδο βασίζεται και εξαρτάται από τη μορφολογία των λέξεων. Μείζον πρόβλημα αποτέλεσε η λεξική ασάφεια, προϊόν της πλούσιας μορφολογίας της ελληνικής γλώσσας. Με δεδομένο αυτό το πρόβλημα σχεδιάστηκε ο σχολιαστής (tagger) με αμιγώς γλωσσολογικά κριτήρια για τις περιπτώσεις εκείνες όπου η λεξική ασάφεια αποτελούσε εμπόδιο στην αποτύπωση λαθών στη χρήση της ελληνικής γλώσσας. Στον γραμματικό διορθωτή δόθηκαν προς διόρθωση κείμενα που είχαν διορθωθεί από άνθρωπο. Σε ένα πολύ μεγάλο ποσοστό ο διορθωτής προσεγγίζει τη διόρθωση του ανθρώπου με μόνη διαφοροποίηση εκείνα τα λάθη που αφορούν τη συνοχή του κειμένου και κατ’ επέκταση όλα τα νοηματικά λάθη. / The aim of this thesis is to design and then to implement a useful and friendly electronic tool (grammar checker) which will carry out the morphological and syntactic analysis of sentences, phrases and words in order to correct syntactic, grammatical and stylistic errors. Our foundation so as to deal with all these issues, is the settings of Grammar (adaptation of Little Modern Grammar of Manolis Triantafyllidis), which is the formalconstituted codified grammar of Modern Greek, since 1976. (In the presentation of this thesis it has not been taken into account the -minimum- differences that appear in the new Greek grammar book of the fifth and sixth grade of the elementary school). Bearing in mind that there is a total absence of such a tool in Greek language, the development of the product is based on the detailed record, on the analysis and on the formulation of the errors of writing speech. Additionally, for its development the right software is chosen in order to describe the grammatical errors. In this thesis the statistics demonstrate the link between the errors and the students’ gender or between the errors and the textual type in which these errors appear. Finnally, through the statistics, the link among the errors and their recognition by the students is presented . This research presents the formalism used (the Mnemosyne) and also the particularities of the Greek language that hinder the computational processing. The formalism has already been used to identify multi-word terms and to phrase grammars, aiming to the automatic information extraction. In this way, all speakers (native or not) will be able to understand better not only the function of various parts of the system of the Greek language but also the way the mechanisms of linguistic analysis operate in the conquest and more broadly in the linguistic realization. The main areas of the grammatical errors with which the grammar checker will interfere, are: 1) Punctuation problems, 2) Final -n, 3) Stylistic issues (verb forms in cases of duplicates, inflectional types), 4) Standardization issues (stereotyped phrases, words of literary origin), 5) Inclination issues (incorrect declension of names or verbs either through ignorance or because of confusion) 6) Vocabulary issues (cases of conceptual confusion, Greek translation of foreign words, redundancy and use of incorrect word or phrase), 7) Orthographic confusion issues (homonymous words), 8) Agreement issues (cases of elements of nominal or verbal phrase disagreement), 9) Syntax issues (verbs) and 10) Cases of errors that require more specialized management of the spelling correction. The basis for the implementation is the electronic morphological lexicon (Neurolingo Lexicon), a 5-level lexicon which consists of, at least 90,000 entries that produce ~1,200,000 inflection types. These types carry information: a) spelling (write spelling of inflectional type), b) morpheme information (type of morphemes: prefix, theme, suffix, ending), c) morphosyntactic information (part of speech, gender, case, person, etc.), d) stylistic information (the stylistic characteristics of the type: oral, archaic, etc.) and e) terminology (additional information about whether the word form is part of a special vocabulary).This electronic lexicon is the foundation that supports the grammar checker. The value and the key role of the morphological lexicon in supporting the Greek grammar checker is obvious, since the first level in which the language is examined is the morphology level and since the structural level is not only based but also depends on the morphology of the words. A major problem in processing the natural language was the lexical ambiguity, a product of the highly morphology of the Greek language. Given that the major problem of modern Greek is the lexical ambiguity we designe the Greek tagger grounded on linguistic criteria for those cases where the lexical ambiguity impede the imprint of the errors in Greek language. The texts that were given for correction to the grammar checker were also corrected by a person. In a very large percentage the grammar checker approximates in accuracy the human-corrector. Only when the grammar checker had to deal with mistakes concerning the coherence of the text or with meaning errors, the humman corrector was the only accurate corrector.

Desvios da norma padrão, comumente chamados de \"erros\", são fatos comuns na escrita dos aprendizes da variante culta de uma língua materna como o português brasileiro. Tratados como um \"mal a ser combatido\", eles são, na verdade, importantes indícios do processo de assimilação da escrita culta pelo falante nativo. Revelam qual a tendência da transformação que naturalmente ocorre numa língua, demonstrando, por exemplo, a obsolência das gramáticas tradicionais, que não aceitam determinadas construções já muito freqüentes. Mas seria possível detectar algum padrão desses desvios? Haveria desvios típicos de um determinado perfil de redatores? Essas indagações motivaram a presente investigação, que se baseou na concepção de que esses estudos são de natureza empírica, comprometidos com a noção de que a língua funciona tal como um sistema probabilístico, de onde é possível prever tendências, por exemplo, de mudança. Falamos, pois, de uma investigação à luz da Lingüística de Corpus. Composto de redações do Exame Nacional do Ensino Médio (ENEM), edição de 2002, cedidas pelo Instituto Nacional de Estudos e Pesquisas Educacionais (INEP) juntamente com determinados traços do perfil dos redatores, construímos um corpus que foi batizado de Corvo, e se ocupou de uma faixa específica de textos: a de pior desempenho no ENEM no quesito domínio da norma culta. Observamos, desse modo, textos em que, supostamente, há freqüência maior de desvios e maior variedade de tipos de desvios. Nossa metodologia de pesquisa apoiou-se no uso do revisor gramatical automático ReGra, bastante popular no país e que auxilia o usuário no uso correto do português culto padrão. Além disso, construímos um material próprio de detecção e classificação dos desvios gramaticais, aumentando a capacidade de tratamento automático dos textos. Assim, foi possível gerar uma versão do corpus anotada em desvios, i.e., os textos apresentam indicações de quando e qual tipo de desvios ocorrem. Como resultado temos um mapeamento do Corvo; ou seja, um panorama dos desvios típicos de um determinado tip o de perfil de redator. Constatamos a deficiência ortográfica como o traço típico do grupo de indivíduos investigado, mas, sobretudo, que a ortografia é motor para o pleno funcionamento de uma revisão gramatical automática. O revisor ReGra mostrou-se incapaz de processar satisfatoriamente textos desse tipo de redator, mas, ainda assim, comprovou que esses textos apresentam desvios gramaticais de tratamento complexo, cuja intervenção do revisor, se acontece, pouco altera na qualidade geral dos mesmos. Com respeito à tipologia de desvio, pudemos constatar a validade da tipologia aplicada na pesquisa, que advém do ReGra e, portanto, está à margem das discussões teóricas ortodoxas. De fato, há recorrência de tipos de desvios, e isso numa freqüência que nos autoriza admitir a fraca assimilação de certas regras gramaticais tomadas como básicas (p.ex., a pontuação, a concordância e a regência). Constatamos, com relação ao perfil de redatores, que textos com maior potencial para a revisão da escrita, i.e., aqueles que alteram significativamente a qualidade textual com interferências pontuais de revisão, são justamente os produzidos pelos concluintes do ensino médio e não pelos egressos. / Deviations from the standard norm, usually called \'mistakes\', are common events in writing pieces of language learners speakers of a native language such as Brazilian Portuguese. They are treated as \'an evil that must be fought\'. They are, in fact, important evidence of the acquisition process of writing in the standard norm by the native speaker. They reveal the transformation trend, which normally occurs in a language, showing, for instance, the obsolescence of traditional grammars that do not accept certain patterns, which are frequent nonetheless. However, is it possible to identify a pattern in these deviations? Are there common deviations among a certain profile of students? These are the questions motivating this study, which is based on the concept that these investigations are empirical in nature, and are marked by the notion that language operates as a probabilistic system, in which it is possible to forecast trends of change, for example. We are, therefore, speaking of an investigation in the light of Corpus Linguistics. We compiled a corpus of essays written during the National Middle Education Exam (ENEM) carried out in 2002. These essays were obtained with the National Institute for Research in Education (INEP) together with the profile of the students. The corpus was called Corvo, and it is made up of a certain bracket of texts: those having obtained the worst performance rate in the ENEM in the standard norm category. We observed, therefore, texts in which there are, allegedly, a greater frequency of deviations and a greater variety of kinds of deviations. The research methodology was supported by the electronic grammar checker - ReGra - which is very popular in the country, and helps the user in writing standard Portuguese correctly. In addition, we built a specific tool for identifying and classifying grammar deviations, thus, increasing the ability to treat the texts electronically. Therefore, it was possible to generate an annotated version of the corpus according to the deviations, i.e., the texts were annotated according to when and what kind of deviations they presented. As a result, we have a mapping of the Corvo; that is, a view of the common deviations of students belonging to a certain profile. We identified poor spelling as a common feature of the group, but, above all, that spelling is the engine enabling a full grammatical check to operate. The ReGra grammar checker was not able to satisfactorily process these kinds of texts, but, even so, it proved that these texts presented complex grammar deviations, and the intervention of the checker, when it is applied, little alters their overall quality. In regard to deviation typology, we identified the validity of the typology used in this study, which results from the ReGra and, therefore, lies in the outskirts of orthodox theoretical discussions. In fact, certain kinds of deviations reoccur at a frequency that enables us to admit a poor assimilation of certain grammatical rules considered basic (e.g., punctuation, agreement and use of prepositions). We found that in regard to the profile of the students, texts with a greater writing check potential, that is, a check that would significantly improve text quality through individual checking interferences, are te xts produced by students who finished middle education and not those produced by students who are finishing the course.

Desvios da norma padrão, comumente chamados de \"erros\", são fatos comuns na escrita dos aprendizes da variante culta de uma língua materna como o português brasileiro. Tratados como um \"mal a ser combatido\", eles são, na verdade, importantes indícios do processo de assimilação da escrita culta pelo falante nativo. Revelam qual a tendência da transformação que naturalmente ocorre numa língua, demonstrando, por exemplo, a obsolência das gramáticas tradicionais, que não aceitam determinadas construções já muito freqüentes. Mas seria possível detectar algum padrão desses desvios? Haveria desvios típicos de um determinado perfil de redatores? Essas indagações motivaram a presente investigação, que se baseou na concepção de que esses estudos são de natureza empírica, comprometidos com a noção de que a língua funciona tal como um sistema probabilístico, de onde é possível prever tendências, por exemplo, de mudança. Falamos, pois, de uma investigação à luz da Lingüística de Corpus. Composto de redações do Exame Nacional do Ensino Médio (ENEM), edição de 2002, cedidas pelo Instituto Nacional de Estudos e Pesquisas Educacionais (INEP) juntamente com determinados traços do perfil dos redatores, construímos um corpus que foi batizado de Corvo, e se ocupou de uma faixa específica de textos: a de pior desempenho no ENEM no quesito domínio da norma culta. Observamos, desse modo, textos em que, supostamente, há freqüência maior de desvios e maior variedade de tipos de desvios. Nossa metodologia de pesquisa apoiou-se no uso do revisor gramatical automático ReGra, bastante popular no país e que auxilia o usuário no uso correto do português culto padrão. Além disso, construímos um material próprio de detecção e classificação dos desvios gramaticais, aumentando a capacidade de tratamento automático dos textos. Assim, foi possível gerar uma versão do corpus anotada em desvios, i.e., os textos apresentam indicações de quando e qual tipo de desvios ocorrem. Como resultado temos um mapeamento do Corvo; ou seja, um panorama dos desvios típicos de um determinado tip o de perfil de redator. Constatamos a deficiência ortográfica como o traço típico do grupo de indivíduos investigado, mas, sobretudo, que a ortografia é motor para o pleno funcionamento de uma revisão gramatical automática. O revisor ReGra mostrou-se incapaz de processar satisfatoriamente textos desse tipo de redator, mas, ainda assim, comprovou que esses textos apresentam desvios gramaticais de tratamento complexo, cuja intervenção do revisor, se acontece, pouco altera na qualidade geral dos mesmos. Com respeito à tipologia de desvio, pudemos constatar a validade da tipologia aplicada na pesquisa, que advém do ReGra e, portanto, está à margem das discussões teóricas ortodoxas. De fato, há recorrência de tipos de desvios, e isso numa freqüência que nos autoriza admitir a fraca assimilação de certas regras gramaticais tomadas como básicas (p.ex., a pontuação, a concordância e a regência). Constatamos, com relação ao perfil de redatores, que textos com maior potencial para a revisão da escrita, i.e., aqueles que alteram significativamente a qualidade textual com interferências pontuais de revisão, são justamente os produzidos pelos concluintes do ensino médio e não pelos egressos. / Deviations from the standard norm, usually called \'mistakes\', are common events in writing pieces of language learners speakers of a native language such as Brazilian Portuguese. They are treated as \'an evil that must be fought\'. They are, in fact, important evidence of the acquisition process of writing in the standard norm by the native speaker. They reveal the transformation trend, which normally occurs in a language, showing, for instance, the obsolescence of traditional grammars that do not accept certain patterns, which are frequent nonetheless. However, is it possible to identify a pattern in these deviations? Are there common deviations among a certain profile of students? These are the questions motivating this study, which is based on the concept that these investigations are empirical in nature, and are marked by the notion that language operates as a probabilistic system, in which it is possible to forecast trends of change, for example. We are, therefore, speaking of an investigation in the light of Corpus Linguistics. We compiled a corpus of essays written during the National Middle Education Exam (ENEM) carried out in 2002. These essays were obtained with the National Institute for Research in Education (INEP) together with the profile of the students. The corpus was called Corvo, and it is made up of a certain bracket of texts: those having obtained the worst performance rate in the ENEM in the standard norm category. We observed, therefore, texts in which there are, allegedly, a greater frequency of deviations and a greater variety of kinds of deviations. The research methodology was supported by the electronic grammar checker - ReGra - which is very popular in the country, and helps the user in writing standard Portuguese correctly. In addition, we built a specific tool for identifying and classifying grammar deviations, thus, increasing the ability to treat the texts electronically. Therefore, it was possible to generate an annotated version of the corpus according to the deviations, i.e., the texts were annotated according to when and what kind of deviations they presented. As a result, we have a mapping of the Corvo; that is, a view of the common deviations of students belonging to a certain profile. We identified poor spelling as a common feature of the group, but, above all, that spelling is the engine enabling a full grammatical check to operate. The ReGra grammar checker was not able to satisfactorily process these kinds of texts, but, even so, it proved that these texts presented complex grammar deviations, and the intervention of the checker, when it is applied, little alters their overall quality. In regard to deviation typology, we identified the validity of the typology used in this study, which results from the ReGra and, therefore, lies in the outskirts of orthodox theoretical discussions. In fact, certain kinds of deviations reoccur at a frequency that enables us to admit a poor assimilation of certain grammatical rules considered basic (e.g., punctuation, agreement and use of prepositions). We found that in regard to the profile of the students, texts with a greater writing check potential, that is, a check that would significantly improve text quality through individual checking interferences, are te xts produced by students who finished middle education and not those produced by students who are finishing the course.