Note: This is about a recipe for the original, English-only Common Voice corpus released in 2018. Subsequent releases with data for various languages are not compatible with this recipe.

Recently, Mozilla published a first version of their Common Voice corpus. It consists of speech prompts from an unknown number of speakers (no speaker IDs are provided due to privacy concerns, see this forum thread). About 254 hours have been validated by multiple listeners. The data has been split into pre-defined training, development and test sets.

I created an initial Kaldi recipe for the corpus as a research exercise. It has since been merged into the Kaldi master branch. Using the pre-defined split into training, development, and test sets, and without any tuning of parameters, a system using a time-delay neural network (TDNN) based acoustic model and a 3-gram language model achieved a WER of 4.27% on the test set; however, given the near-complete overlap in spoken utterances between the training, development, and test sets, these results are not very meaningful in terms of generalization to other datasets. See this issue for an ongoing discussion on how the data collection effort could be improved.