Vocabulary Speech Recognition via Telephone

Due to the need for a flexible vocabulary and the high cost of collecting speech corpora, vocabulary independence of speech recognition systems has grown to be a significant issue. We describe the steps required to reach the objective of vocabulary-independent speech recognition and discuss our experimental experience with telephone speech recognition.
There were two sets of experiments: 1) Wcommand recognition, where we compared vocabulary-independent (VI) and vocabulary-dependent (VD) systems as well as phonetic and word-based systems, and 2) 42-city name recognition, where our vocabulary independent recognition performance (8.5% W. Err. ) was very close to the VD performance (8%) of the Oregon Graduate Institute (OGI), which was reported by OGI, but significantly better than the VI performance (18%).
Finally, we can say that some progress has been made. We identify the areas for improvement that are likely to move us closer to the goal of vocabulary independence, but much work needs to be done.