Multilingual Word Embeddings (MWEs) represent words from multiple languages
in a single distributional vector space. Unsupervised MWE (UMWE) methods
acquire multilingual embeddings without cross-lingual supervision, which is a
significant advantage over traditional supervised approaches and opens many new
possibilities for low-resource languages. Prior art for learning UMWEs,
however, merely relies on a number of independently trained Unsupervised
Bilingual Word Embeddings (UBWEs) to obtain multilingual embeddings. These
methods fail to leverage the interdependencies that exist among many languages.
To address this shortcoming, we propose a fully unsupervised framework for
learning MWEs that directly exploits the relations between all language pairs.
Our model substantially outperforms previous approaches in the experiments on
multilingual word translation and cross-lingual word similarity. In addition,
our model even beats supervised approaches trained with cross-lingual
resources.

提出了一种全新的多语言词向量空间的无监督学习框架，该框架可以直接捕捉不同语言之间的交互关系，从而显著提高多语种单词转换和跨语种单词相似度的效果，并且比使用跨语种资源的监督式方法表现更好。