We propose a new benchmark corpus to be used for measuring progress in statistical
language modeling. With almost one billion words of training data, we hope this
benchmark will be useful to quickly evaluate novel language modeling techniques,
and to compare their contribution when combined with other advanced techniques.
We show performance of several well-known types of language models, with the
best results achieved with a recurrent neural network based language model.
The baseline unpruned Kneser-Ney 5-gram model achieves perplexity 67.6. A combination
of techniques leads to 35% reduction in perplexity, or 10% reduction in cross-entropy
(bits), over that baseline.
The benchmark is available as a code.google.com project; besides the scripts needed to rebuild the training/held-out data, it also makes available log-probability values for each word in each of ten held-out data sets, for each of the baseline N-gram models.
Bibliographic reference. Chelba, Ciprian / Mikolov, Tomas / Schuster, Mike / Ge, Qi / Brants, Thorsten / Koehn, Phillipp / Robinson, Tony (2014): "One billion word benchmark for measuring progress in statistical language modeling", In INTERSPEECH-2014, 2635-2639.