Zero-Shot Cross-lingual Classification Using Multilingual Neural Machine Translation
Table 4: Results of the control experiment on zero-shot performance on the Amazon German test set.
['[BOLD] Model', 'Amazon (De)']
The third row in the table shows the small deviation of 7% over random, which is likely obtained from common sub-words having similar meaning across languages. This control experiment suggests that although having a shared sub-word vocabulary is necessary, we still need to train the NMT system on parallel data from the language of interest so that the system can perform zero-shot classification.