Portable spelling corrector for a less-resourced language: Amharic

Abstract

This paper describes an automatic spelling corrector for Amharic, the working language of the Federal Government of Ethiopia. We used a corpus-driven approach with the noisy channel for spelling correction. It infers linguistic knowledge from a text corpus. The approach can be ported to other written languages with little effort as long as they are typed using a QWERTY keyboard with direct mappings between keystrokes and characters. Since Amharic letters are syllabic, we used a modified version of the System for Ethiopic Representation in ASCII for transliteration in the like manner as most Amharic keyboard input methods do. The proposed approach is evaluated with Amharic and English test data and has scored better performance result than the baseline systems: GNU Aspell and Hunspell. We get better result due to the smoothed language model, the generalized error model and the ability to take into account the context of misspellings. Besides, instead of using a handcrafted lexicon for spelling error detection, we used a term list derived from frequently occurring terms in a text corpus. Such a term list, in addition to ease of compilation, has also an advantage in handling rare terms, proper nouns, and neologisms.