Korean large vocabulary continuous speech recognition using pseudomorpheme units

Abstract

This paper presents a Korean large vocabulary continuous speech recognition system based on pseudomorpheme units. In Korean, an eojeol (word phrase) is a unit for spacing and a morpheme is the smallest unit with semantic meaning. If the eojeol is used as the dictionary and language modeling unit, the number of the unit becomes enormous. Instead we propose to use modified morpheme or pseudomorpheme as the basic recognition unit. We can recover the original eojeol by concatenating graphemes of pseudomorpheme components. We used a dictionary and language model with pseudomorpheme/part-ofspeech entries where each entry can have multiple pronunciations according to the morphology rule. With 32k-word vocabulary, the speaker-independent character, pseudomorpheme, and eojeol recognition accuracies on economy article database were 90.8%, 84.5%, and 81.3%, respectively.