Stemming Indonesian

Stemming words to (usually) remove suffixes has applications in text search, machine translation, document summarisation, and text classification. For example, English stemming reduces the words “computer”, “computing”, “computation”, and “computability” to their common morphological root, “comput-”. In text search, this permits a search for “computers” to find documents containing all words with the stem “comput-”. In the Indonesian language, stemming is of crucial importance: words have prefixes, suffixes, infixes, and confixes that make matching related words difficult. In this paper, we investigate the performance of five Indonesian stemming algorithms through a user study. Our results show that, with the availability of a reasonable dictionary, the unpublished algorithm of Nazief and Adriani correctly stems around 93% of word occurrences to the correct root word. With the improvements we propose, this almost reaches 95%. We conclude that stemming for Indonesian should be performed using our modified Nazief and Adriani approach.