虽然最近关于多语种语言模型的工作已经证明了他们对下游任务的交叉零射击传输的能力，但社区缺乏符合语言之间的共享属性，可以实现这种转移。涉及成对的自然语言的分析通常是不确定的，并且矛盾以来，许多语言方面同时不同。在本文中，我们进行大规模的实证研究，通过测量四种不同的自然语言和通过修改脚本，单词顺序和语法等方面构造的零拍摄传递来隔离各种语言特性的影响。在其他事情之外，我们的实验表明，当语言的单词顺序不同时，缺乏子字重叠显着影响零拍摄传输，并且在语言之间的传输性能和Word嵌入对准之间存在强烈相关性（例如，r = 0.94关于NLI的任务）。我们的结果呼吁专注于在明确改进语言之间的嵌入对齐而不是依赖于隐含的出现。

多语言语言模型（\ mllms），如mbert，xlm，xlm-r，\ textit {etc。}已成为一种可行的选择，使预先估计到大量语言的力量。鉴于他们的成功在零射击转移学习中，在（i）建立更大的\ mllms〜覆盖了大量语言（ii）创建覆盖更广泛的任务和语言来评估的详尽工作基准mllms〜（iii）分析单音零点，零拍摄交叉和双语任务（iv）对Monolingual的性能，了解\ mllms〜（v）增强（通常）学习的通用语言模式（如果有的话）有限的容量\ mllms〜以提高他们在已见甚至看不见语言的表现。在这项调查中，我们审查了现有的文学，涵盖了上述与\ MLLMS有关的广泛研究领域。根据我们的调查，我们建议您有一些未来的研究方向。

In this paper, we show that Multilingual BERT (M-BERT), released by Devlin et al. (2019) as a single language model pre-trained from monolingual corpora in 104 languages, is surprisingly good at zero-shot cross-lingual model transfer, in which task-specific annotations in one language are used to fine-tune the model for evaluation in another language. To understand why, we present a large number of probing experiments, showing that transfer is possible even to languages in different scripts, that transfer works best between typologically similar languages, that monolingual corpora can train models for code-switching, and that the model can find translation pairs. From these results, we can conclude that M-BERT does create multilingual representations, but that these representations exhibit systematic deficiencies affecting certain language pairs.

Much recent progress in applications of machine learning models to NLP has been driven by benchmarks that evaluate models across a wide variety of tasks. However, these broad-coverage benchmarks have been mostly limited to English, and despite an increasing interest in multilingual models, a benchmark that enables the comprehensive evaluation of such methods on a diverse range of languages and tasks is still missing. To this end, we introduce the Cross-lingual TRansfer Evaluation of Multilingual Encoders (XTREME) benchmark, a multi-task benchmark for evaluating the cross-lingual generalization capabilities of multilingual representations across 40 languages and 9 tasks. We demonstrate that while models tested on English reach human performance on many tasks, there is still a sizable gap in the performance of cross-lingually transferred models, particularly on syntactic and sentence retrieval tasks. There is also a wide spread of results across languages. We release the benchmark 1 to encourage research on cross-lingual learning methods that transfer linguistic knowledge across a diverse and representative set of languages and tasks.

Multi-lingual language models (LM), such as mBERT, XLM-R, mT5, mBART, have been remarkably successful in enabling natural language tasks in low-resource languages through cross-lingual transfer from high-resource ones. In this work, we try to better understand how such models, specifically mT5, transfer *any* linguistic and semantic knowledge across languages, even though no explicit cross-lingual signals are provided during pre-training. Rather, only unannotated texts from each language are presented to the model separately and independently of one another, and the model appears to implicitly learn cross-lingual connections. This raises several questions that motivate our study, such as: Are the cross-lingual connections between every language pair equally strong? What properties of source and target language impact the strength of cross-lingual transfer? Can we quantify the impact of those properties on the cross-lingual transfer? In our investigation, we analyze a pre-trained mT5 to discover the attributes of cross-lingual connections learned by the model. Through a statistical interpretation framework over 90 language pairs across three tasks, we show that transfer performance can be modeled by a few linguistic and data-derived features. These observations enable us to interpret cross-lingual understanding of the mT5 model. Through these observations, one can favorably choose the best source language for a task, and can anticipate its training data demands. A key finding of this work is that similarity of syntax, morphology and phonology are good predictors of cross-lingual transfer, significantly more than just the lexical similarity of languages. For a given language, we are able to predict zero-shot performance, that increases on a logarithmic scale with the number of few-shot target language data points.

In this work, we introduce IndicXTREME, a benchmark consisting of nine diverse tasks covering 18 languages from the Indic sub-continent belonging to four different families. Across languages and tasks, IndicXTREME contains a total of 103 evaluation sets, of which 51 are new contributions to the literature. To maintain high quality, we only use human annotators to curate or translate\footnote{for IndicXParaphrase, where an automatic translation system is used, a second human verification and correction step is done.} our datasets. To the best of our knowledge, this is the first effort toward creating a standard benchmark for Indic languages that aims to test the zero-shot capabilities of pretrained language models. We also release IndicCorp v2, an updated and much larger version of IndicCorp that contains 20.9 billion tokens in 24 languages. We pretrain IndicBERT v2 on IndicCorp v2 and evaluate it on IndicXTREME to show that it outperforms existing multilingual language models such as XLM-R and MuRIL.

Universal cross-lingual sentence embeddings map semantically similar cross-lingual sentences into a shared embedding space. Aligning cross-lingual sentence embeddings usually requires supervised cross-lingual parallel sentences. In this work, we propose mSimCSE, which extends SimCSE to multilingual settings and reveal that contrastive learning on English data can surprisingly learn high-quality universal cross-lingual sentence embeddings without any parallel data. In unsupervised and weakly supervised settings, mSimCSE significantly improves previous sentence embedding methods on cross-lingual retrieval and multilingual STS tasks. The performance of unsupervised mSimCSE is comparable to fully supervised methods in retrieving low-resource languages and multilingual STS. The performance can be further enhanced when cross-lingual NLI data is available. Our code is publicly available at https://github.com/yaushian/mSimCSE.

多语言预训练的语言模型在跨语言任务上表现出了令人印象深刻的表现。它极大地促进了自然语言处理在低资源语言上的应用。但是，当前的多语言模型仍然有些语言表现不佳。在本文中，我们提出了Cino（中国少数族裔训练的语言模型），这是一种用于中国少数语言的多语言预训练的语言模型。它涵盖了标准的中文，Yue中文和其他六种少数民族语言。为了评估多语言模型在少数族裔语言上的跨语性能力，我们从Wikipedia和新闻网站收集文档，并构建两个文本分类数据集，WCM（Wiki-Chinese-Minority）和CMNEWS（中国最少的新闻）。我们表明，Cino在各种分类任务上的表现明显优于基准。Cino模型和数据集可在http://cino.hfl-rc.com上公开获得。

Translating training data into many languages has emerged as a practical solution for improving cross-lingual transfer. For tasks that involve span-level annotations, such as information extraction or question answering, an additional label projection step is required to map annotated spans onto the translated texts. Recently, a few efforts have utilized a simple mark-then-translate method to jointly perform translation and projection by inserting special markers around the labeled spans in the original sentence. However, as far as we are aware, no empirical analysis has been conducted on how this approach compares to traditional annotation projection based on word alignment. In this paper, we present an extensive empirical study across 42 languages and three tasks (QA, NER, and Event Extraction) to evaluate the effectiveness and limitations of both methods, filling an important gap in the literature. Experimental results show that our optimized version of mark-then-translate, which we call EasyProject, is easily applied to many languages and works surprisingly well, outperforming the more complex word alignment-based methods. We analyze several key factors that affect end-task performance, and show EasyProject works well because it can accurately preserve label span boundaries after translation. We will publicly release all our code and data.

We present, Naamapadam, the largest publicly available Named Entity Recognition (NER) dataset for the 11 major Indian languages from two language families. In each language, it contains more than 400k sentences annotated with a total of at least 100k entities from three standard entity categories (Person, Location and Organization) for 9 out of the 11 languages. The training dataset has been automatically created from the Samanantar parallel corpus by projecting automatically tagged entities from an English sentence to the corresponding Indian language sentence. We also create manually annotated testsets for 8 languages containing approximately 1000 sentences per language. We demonstrate the utility of the obtained dataset on existing testsets and the Naamapadam-test data for 8 Indic languages. We also release IndicNER, a multilingual mBERT model fine-tuned on the Naamapadam training set. IndicNER achieves the best F1 on the Naamapadam-test set compared to an mBERT model fine-tuned on existing datasets. IndicNER achieves an F1 score of more than 80 for 7 out of 11 Indic languages. The dataset and models are available under open-source licenses at https://ai4bharat.iitm.ac.in/naamapadam.

编码单词语义属性的密集词向量或“Word Embeddings”现在已成为机器翻译（MT），问题应答（QA），字感消解（WSD）和信息检索（IR）中的NLP任务的积分。在本文中，我们使用各种现有方法为14个印度语言创建多个单词嵌入。我们将这些嵌入的嵌入式为所有这些语言，萨姆萨姆，孟加拉，古吉拉蒂，印地教派，kannada，konkani，malayalam，marathi，尼泊尔，odiya，punjabi，梵语，泰米尔和泰雅古士在一个单一的存储库中。相对较新的方法，强调迎合上下文（BERT，ELMO等），表明了显着的改进，但需要大量资源来产生可用模型。我们释放使用上下文和非上下文方法生成的预训练嵌入。我们还使用Muse和XLM来培训所有上述语言的交叉语言嵌入。为了展示我们嵌入的效果，我们为所有这些语言评估了我们对XPOS，UPOS和NER任务的嵌入模型。我们使用8种不同的方法释放了436个型号。我们希望他们对资源受限的印度语言NLP有用。本文的标题是指最初在1924年出版的福斯特的着名小说“一段是印度”。

一些基于变压器的模型可以执行跨语言转移学习：这些模型可以通过一种语言对特定任务进行培训，并以另一种语言的同一任务给予相对良好的结果，尽管仅在单语任务中进行了预先培训。但是，关于这些基于变压器的模型是否学习跨语言的通用模式，目前尚无共识。我们提出了一种单词级的任务不可能的方法，以评估此类模型构建的上下文化表示的对齐方式。我们表明，与以前的方法相比，我们的方法提供了更准确的翻译成对，以评估单词级别对齐。我们的结果表明，基于多语言变压器模型的某些内部层优于其他明确对齐的表示，甚至根据多语言对齐的更严格的定义，更是如此。

Cross-lingual transfer learning without labeled target language data or parallel text has been surprisingly effective in zero-shot cross-lingual classification, question answering, unsupervised machine translation, etc. However, some recent publications have claimed that domain mismatch prevents cross-lingual transfer, and their results show that unsupervised bilingual lexicon induction (UBLI) and unsupervised neural machine translation (UNMT) do not work well when the underlying monolingual corpora come from different domains (e.g., French text from Wikipedia but English text from UN proceedings). In this work, we show that a simple initialization regimen can overcome much of the effect of domain mismatch in cross-lingual transfer. We pre-train word and contextual embeddings on the concatenated domain-mismatched corpora, and use these as initializations for three tasks: MUSE UBLI, UN Parallel UNMT, and the SemEval 2017 cross-lingual word similarity task. In all cases, our results challenge the conclusions of prior work by showing that proper initialization can recover a large portion of the losses incurred by domain mismatch.

在多语言甚至单语言中鉴定的模型的零拍跨语言能力刺激了许多假设，以解释这一有趣的经验结果。但是，由于预处理的成本，大多数研究都使用公共模型的公共模型，其预处理方法（例如代币化，语料库规模和计算预算的选择）可能会大不相同。当研究人员对自己的模型预识时，他们通常会在预算有限的情况下这样做，并且与SOTA模型相比，最终的模型的表现可能明显不足。这些实验差异导致有关这些模型跨语性能力的性质的各种不一致的结论。为了帮助对该主题进行进一步研究，我们发布了10个单语字节级模型，并在相同的配置下进行了严格审慎的概述，并具有大型计算预算（相当于V100的420天）和Corpora，比原始BERT大4倍。由于它们不含令牌，因此消除了看不见的令牌嵌入的问题，从而使研究人员可以在具有不同脚本的语言中尝试更广泛的跨语言实验。此外，我们释放了在不自然语言文本上预测的两个模型，这些模型可用于理智检查实验。关于质量检查和NLI任务的实验表明，我们的单语模型实现了多语言的竞争性能，因此可以加强我们对语言模型中跨语性可传递性的理解。

翻译质量估计（QE）是预测机器翻译（MT）输出质量的任务，而无需任何参考。作为MT实际应用中的重要组成部分，这项任务已越来越受到关注。在本文中，我们首先提出了XLMRScore，这是一种基于使用XLM-Roberta（XLMR）模型计算的BertScore的简单无监督的QE方法，同时讨论了使用此方法发生的问题。接下来，我们建议两种减轻问题的方法：用未知令牌和预训练模型的跨语性对准替换未翻译的单词，以表示彼此之间的一致性单词。我们在WMT21 QE共享任务的四个低资源语言对上评估了所提出的方法，以及本文介绍的新的英语FARSI测试数据集。实验表明，我们的方法可以在两个零射击方案的监督基线中获得可比的结果，即皮尔森相关性的差异少于0.01，同时在所有低资源语言对中的平均低资源语言对中的无人看管竞争对手的平均水平超过8％的平均水平超过8％。 。

与辅助语言的元学习已经表明了对交叉语言自然语言处理的有希望的改进。然而，以前的研究采样使用相同语言的元培训和元测试数据，这限制了模型交叉传输的能力。在本文中，我们提出了XLA-MAML，在元学习阶段执行直接交叉调整。我们对自然语言推理和问题进行零射击和几次拍摄实验。实验结果表明了我们在不同语言，任务和预磨料模型中的方法的有效性。我们还对元学习的各种交叉特定设置进行了分析，包括采样策略和并行性。

最近，大型预用语言模型（LMS）越来越受欢迎。培训这些模型需要更多的计算资源，并且大多数现有模型仅在英文文本上培训。以其他语言训练这些模型非常昂贵。为了缓解这个问题，我们介绍了一种叫做威施塞的方法 - 将英语模型传输到新语言。我们将英语模型的销量与目标语言中的销量交换，并初始化令牌嵌入式，以便通过利用覆盖英语和目标语言的多语言静态字嵌入来初始化令牌嵌入式。我们使用Wechsel将GPT-2和Roberta模型转移到4种其他语言（法语，德语，中文和斯瓦希里语）。 Wechsel通过以前提出的跨语言参数转移和优于比较大小的模型来改善从目标语言的划痕训练的相当大小的型号，距离培训速度较小。我们的方法使培训大型语言模型为新语言更容易访问，更少损害环境。我们宣传我们的代码和型号。

在过去几年中，已经提出了多语言预训练的语言模型（PLMS）的激增，以实现许多交叉曲线下游任务的最先进的性能。但是，了解为什么多语言PLMS表现良好仍然是一个开放域。例如，目前尚不清楚多语言PLM是否揭示了不同语言的一致令牌归因。要解决此问题，请在本文中提出了令牌归因（CCTA）评估框架的交叉致新一致性。三个下游任务中的广泛实验表明，多语言PLMS为多语素同义词分配了显着不同的归因。此外，我们有以下观察结果：1）当它用于培训PLMS时，西班牙语在不同语言中实现了最常见的令牌归属;2）令牌归属的一致性与下游任务中的性能强烈相关。

多语种预训练模型在许多多语言NLP任务中展示了它们的有效性，并使从高资源语言到低资源的零射击或几秒钟传输。然而，由于某种语言之间的显着的类型差异和矛盾，这些模型通常在许多语言和交叉语言设置上表现不佳，这表明了学习单一模型同时处理大规模不同语言的难度。为了减轻这个问题，我们提出了一个新的多语言预训练管道。我们建议从多语言预先训练的模型产生语言表示，并进行语言分析，以表明语言表示相似度反映了从多个角度来看的语言相似度，包括语言家庭，地理蓝星，词汇表演和语法。然后，我们将所有目标语言集成到多个组中，并将每个组名称为表示SprachBund。因此，在同一表示SprachBund中的语言应该在培训和微调中互相提升，因为它们共享丰富的语言相似性。我们预先列车为每个代表斯普拉克班达一个多语言模型。实验在交叉基准上进行，与强基线相比，实现了显着的改进。

最近的工作表明，通过多语种伯爵（MBENT）获得的知识有两个组件：特定于语言和语言中立的。本文分析了它们之间的关系，在两项任务的微调 - POS标记和自然语言推理的背景下 - 需要模型带来不同的语言特异性知识。可视化揭示MBERT失去了在微调后通过语言进行群集表示的能力，这是通过语言识别实验的证据支持的结果。然而，显示使用梯度逆转和迭代对抗性学习的“无学习”语言特定表示的进一步实验，不会在微调的效果之外增加对独立于语言无关的组件的进一步改进。此处提出的结果表明，微调的过程导致模型的重组有限的代表能力，以特定于语言特定的代表性的语言无关的表示。