In this paper, we use the framework of neural machine translation to learn
joint sentence representations across six very different languages. Our aim is
that a representation which is independent of the language, is likely to
capture the underlying semantics. We define a new cross-lingual similarity
measure, compare up to 1.4M sentence representations and study the
characteristics of close sentences. We provide experimental evidence that
sentences that are close in embedding space are indeed semantically highly
related, but often have quite different structure and syntax. These relations
also hold when comparing sentences in different languages.

本研究使用神经机器翻译框架跨越六种完全不同的语言，在学习联合句子表示方面。我们的目标是构建一种与语言无关的表示形式，有可能捕捉到基础的语义。我们定义了一种新的跨语言相似度衡量方式，对我们的模型学习出的 140 万个句子表示进行比较，并研究了相似句子的特征。实验证据表明，嵌入空间中相似的句子实际上具有高度的语义相关性，但通常具有不同的结构和语法。这种关系也适用于不同语言之间的比较。