An efficient method for vocabulary addition to WFST graphs

Abstract

A successful application of automatic speech recognition often requires the ability to recognize words that are not known during system building phase. Modern speech recognition decoders employ large WFST graphs so to add new words one needs to recompile the graph. The compilation process requires a lot of memory and consumes a lot of time. In this paper a method to add new words into a speech recognition graph is presented. The method requires significantly less memory, takes less time than a full recompilation and doesn’t affect recognition accuracy or speed.