The Rule-Based Sundanese Stemmer

Abstract

Our research proposed an iterative Sundanese stemmer by removing the derivational affixes prior to the inflexional. This scheme was chosen because, in the Sundanese affixation, a confix (one of derivational affix) is applied in the last phase of a morphological process. Moreover, most of Sundanese affixes are derivational, so removing the derivational affix as the first step is reasonable. To handle ambiguity, the last recognized affix was returned as the result. As the baseline, a Confix-Stripping Approach that applies Porter Stemmer for the Indonesian language was used. This stemmer shares similarities in terms of affix type, but uses a different stemming order. To observe whether the baseline stems the Sundanese affixed word properly, some features that were not covered by the baseline, such as the infix and allomorph removal, were added. The evaluation was done using 4,453 unique affixed words collected from Sundanese online magazines. The experiment shows that, as a whole, our stemmer outperforms the modified baseline in terms of recognized affixed type accuracy and properly stemmed affixed words. Our stemmer recognized 68.87% of the Sundanese affixed types and produced 96.79% of the correctly affixed words; the modified baseline resulted in 21.70% and 71.59%, respectively