Cross-lingual Dependency Parsing with Unlabeled Auxiliary Languages
Table 6: Average cross-lingual transfer performances (UAS%/LAS%, w/o punctuation) on the test sets using SelfAtt-Graph parser when different languages play the role of the auxiliary language in adversarial training.
['Aux. lang', 'Avg. Dist. to other lang', 'multilingual Word Emb.', 'multilingual BERT']
Intuitively, we would assume when the auxiliary language has a smaller average distance to all the target languages, the cross-lingual transfer performance would be better. For example, Portuguese (pt) has the smallest average distance to other languages among the auxiliary languages we tested, but it is not among the better auxiliary languages.