Abstract: The lack of large-scale datasets has been a major hindrance to the development of NLP tasks such as spelling correction and grammatical error correction (GEC). As a complementary new resource for these tasks, we present the GitHub Typo Corpus, a large-scale, multilingual dataset of misspellings and grammatical errors along with their corrections harvested from GitHub, a large and popular platform for hosting and sharing git repositories. The dataset, which we have made publicly available, contains more than 350k edits and 65M characters in more than 15 languages, making it the largest dataset of misspellings to date. We also describe our process for filtering true typo edits based on learned classifiers on a small annotated subset, and demonstrate that typo edits can be identified with F1 ~ 0.9 using a very simple classifier with only three features. The detailed analyses of the dataset show that existing spelling correctors merely achieve an F-measure of approx. 0.5, suggesting that the dataset serves as a new, rich source of spelling errors that complement existing datasets.

Introduction: Spelling correction BIBREF0, BIBREF1, BIBREF2 and grammatical error correction (GEC) BIBREF3 are two fundamental tasks that have important implications for downstream NLP tasks and for education in general. In recent years, the use of statistical machine translation (SMT) and neural sequence-to-sequence (seq2seq) models has been becoming increasingly popular for solving these tasks. Such modern NLP models are usually data hungry and require a large amount of parallel training data consisting of sentences before and after the correction. However, only relatively small datasets are available for these tasks, compared to other NLP tasks such as machine translation. This is especially the case for spelling correction, for which only a small number of datasets consisting of individual misspelled words are available, including the Birkbeck spelling error corpus and a list of typos collected from Twitter. Due to this lack of large-scale datasets, many research studies BIBREF4, BIBREF2, BIBREF5 resort to automatic generation of artificial errors (also called pseudo-errors). Although such methods are efficient and have seen some success, they do not guarantee that generated errors reflect the range and the distribution of true errors made by humans BIBREF6. As one way to complement this lack of resources, Wikipedia has been utilized as a rich source of textual edits, including typos BIBREF7, BIBREF8, BIBREF9. However, the edits harvested from Wikipedia are often very noisy and diverse in their types, containing edits from typos to adding and modifying information. To make the matters worse, Wikipedia suffers from vandalism, where articles are edited in a malicious manner, which requires extensive detection and filtering. In order to create a high-quality, large-scale dataset of misspelling and grammatical errors (collectively called typos in this paper), we leverage the data from GitHub, the largest platform for hosting and sharing repositories maintained by git, a popular version control system commonly used for software development. Changes made to git repositories (called commits, see Section 3 for the definition) are usually tagged with commit messages, making detection of typos a trivial task. Also, GitHub suffers less from vandalism, since commits in many repositories are code reviewed, a process where every change is manually reviewed by other team members before merged into the repository. This guarantees that the edits indeed fix existing spelling and/or grammatical issues. This paper describes our process for building the GitHub Typo Corpus, a large-scale, multilingual dataset of misspellings and grammatical errors, along with their corrections. The process for building the dataset can be summarized as follows: Extract eligible repositories and typo commits from GitHub based on the meta data of the repository and the commit message Filter out edits that are not written in human language Identify true typo edits (vs semantic edits) by using learned classifiers on a small annotated dataset We demonstrate that a very simple logistic regression model with only three features can classify typos and non-typo edits correctly with $F1 \sim 0.9$. This resulted in a dataset containing more than 350k edits and 64M characters in more than 15 languages. To the best of our knowledge, this is the largest multilingual dataset of misspellings to date. We made the dataset publicly available (https://github.com/mhagiwara/github-typo-corpus) along with the automatically assigned typo labels as well as the source code to extract typos. We also provide the detailed analyses of the dataset, where we demonstrate that the F measure of existing spell checkers merely reaches $\sim 0.5$, arguing that the GitHub Typo Corpus provides a new, rich source of naturally-occurring misspellings and grammatical errors that complement existing datasets.

Question: Which languages are covered in the corpus?
Answer: English, Chinese, Japanese, Russian, French, German, Portugese, Spanish, Korean, Hindi and Others