  Much of the recent literature on automatic speech recognition (ASR) is taking
an end-to-end approach. Unlike English where the writing system is closely
related to sound, Chinese characters (Hanzi) represent meaning, not sound. We
propose factoring audio -> Hanzi into two sub-tasks: (1) audio -> Pinyin and
(2) Pinyin -> Hanzi, where Pinyin is a system of phonetic transcription of
standard Chinese. Factoring the audio -> Hanzi task in this way achieves 3.9%
CER (character error rate) on the Aishell-1 corpus, the best result reported on
this dataset so far.
