XL-WA: a Gold Evaluation Benchmark for Word Alignment in 14 Language Pairs

Word alignment plays a crucial role in several NLP tasks, such as lexicon injection and cross-lingual label projection. The evaluation of word alignment systems relies heavily on manually-curated datasets, which are not always available, especially in mid-and low-resource languages. In order to address this limitation, we propose XL-WA, a novel entirely manually-curated evaluation benchmark for word alignment covering 14 language pairs. We illustrate the creation process of our benchmark and compare statistical and neural approaches to word alignment in both language-specific and zero-shot settings, thus investigating the ability of state-of-the-art models to generalize on unseen language pairs. We release our new benchmark at: https://github.com/SapienzaNLP/XL-WA.