Social media enables the rapid spread of many kinds of information, from memes to social movements. However, little is known about how information crosses linguistic boundaries. We apply causal inference techniques on the European Twitter network to quantify multilingual users' structural role and communication influence in cross-lingual information exchange. Overall, multilinguals play an essential role; posting in multiple languages increases betweenness centrality by 13%, and having a multilingual network neighbor increases monolinguals' odds of sharing domains and hashtags from another language 16-fold and 4-fold, respectively. We further show that multilinguals have a greater impact on diffusing information less accessible to their monolingual compatriots, such as information from far-away countries and content about regional politics, nascent social movements, and job opportunities. By highlighting information exchange across borders, this work sheds light on a crucial component of how information and ideas spread around the world.

翻译：社交媒体使各类信息（从网络迷因到社会运动）得以快速传播。然而，信息如何跨越语言边界尚不明确。我们运用因果推断技术，基于欧洲推特网络量化多语用户的结构角色及其在跨语言信息交换中的传播影响力。总体而言，多语者发挥着关键作用：使用多种语言发帖可使中介中心性提升13%，而拥有多语邻居的单一语言用户，其跨语言共享域名和话题标签的几率分别跃升16倍和4倍。我们进一步证明：多语者对于传播其同语种同胞难以获取的信息（如来自遥远国度的信息、区域政治议题、新兴社会运动及就业机会相关内容）具有更大影响力。通过聚焦跨境信息交换，本研究揭示了信息和思想在全球传播的关键机制。