Adaptive Spelling Error Correction Models for Learner English

Spelling errors are a characteristic of learner English and degrade the performances of natural language processing systems targeting English learners. This paper describes a method specially designed for automatically correcting spelling errors in learner English that reduces the effects from noise (e.g., grammatical and spelling errors) by adaptively creating spelling error correction models from raw learner corpora. An evaluation shows that the proposed method outperforms previous edit-distance-based and language-model-based methods. We also report results of an investigation into what types of spelling errors English learners tend to make, using the spelling error models created by the proposed method as a tool for our analysis.