Probing with Noise: Unpicking the Warp and Weft of Taxonomic and Thematic Meaning Representations in Static and Contextual Embeddings

The semantic relatedness of words has two key dimensions: it can be based on taxonomic information or thematic, co-occurrence-based information. These are captured by different language resources—taxonomies and natural corpora—from which we can build different computational meaning representations that are able to reflect these relationships. Vector representations are arguably the most popular meaning representations in NLP, encoding information in a shared multidimensional semantic space and allowing for distances between points to reflect relatedness between items that populate the space. Improving our understanding of how different types of linguistic information are encoded in vector space can provide valuable insights to the field of model interpretability and can further our understanding of different encoder architectures. Alongside vector dimensions, we argue that information can be encoded in more implicit ways and hypothesise that it is possible for the vector magnitude—the norm—to also carry linguistic information. We develop a method to test this hypothesis and provide a systematic exploration of the role of the vector norm in encoding the different axes of semantic relatedness across a variety of vector representations, including taxonomic, thematic, static and contextual embeddings. The method is an extension of the standard probing framework and allows for relative intrinsic interpretations of probing results. It relies on introducing targeted noise that ablates information encoded in embeddings and is grounded by solid baselines and confidence intervals. We call the method probing with noise and test the method at both the word and sentence level, on a host of established linguistic probing tasks, as well as two new semantic probing tasks: hypernymy and idiomatic usage detection. Our experiments show that the method is able to provide geometric insights into embeddings and can demonstrate whether the norm encodes the linguistic information being probed for. This confirms the existence of separate information containers in English word2vec, GloVe and BERT embeddings. The experiments and complementary analyses show that different encoders encode different kinds of linguistic information in the norm: taxonomic vectors store hypernym-hyponym information in the norm, while non-taxonomic vectors do not. Meanwhile, non-taxonomic GloVe embeddings encode syntactic and sentence length information in the vector norm, while the contextual BERT encodes contextual incongruity. Our method can thus reveal where in the embeddings certain information is contained. Furthermore, it can be supplemented by an array of post-hoc analyses that reveal how information is encoded as well, thus offering valuable structural and geometric insights into the different types of embeddings

Fine-grained human evaluation of neural versus phrase-based machine translation

We compare three approaches to statistical machine translation (pure phrase-based, factored phrase-based and neural) by performing a fine-grained manual evaluation via error annotation of the systems' outputs. The error types in our annotation are compliant with the multidimensional quality metrics (MQM), and the annotation is performed by two annotators. Inter-annotator agreement is high for such a task, and results show that the best performing system (neural) reduces the errors produced by the worst system (phrase-based) by 54%.Comment: 12 pages, 2 figures, The Prague Bulletin of Mathematical Linguistic

Is it worth it? Budget-related evaluation metrics for model selection

Creating a linguistic resource is often done by using a machine learning model that filters the content that goes through to a human annotator, before going into the final resource. However, budgets are often limited, and the amount of available data exceeds the amount of affordable annotation. In order to optimize the benefit from the invested human work, we argue that deciding on which model one should employ depends not only on generalized evaluation metrics such as F-score, but also on the gain metric. Because the model with the highest F-score may not necessarily have the best sequencing of predicted classes, this may lead to wasting funds on annotating false positives, yielding zero improvement of the linguistic resource. We exemplify our point with a case study, using real data from a task of building a verb-noun idiom dictionary. We show that, given the choice of three systems with varying F-scores, the system with the highest F-score does not yield the highest profits. In other words, in our case the cost-benefit trade off is more favorable for a system with a lower F-score.Comment: 7 pages, 1 figure, 5 tables, In proceedings of the Eleventh International Conference on Language Resources and Evaluation (LREC 2018

Quantitative Fine-Grained Human Evaluation of Machine Translation Systems: a Case Study on English to Croatian

This paper presents a quantitative fine-grained manual evaluation approach to comparing the performance of different machine translation (MT) systems. We build upon the well-established Multidimensional Quality Metrics (MQM) error taxonomy and implement a novel method that assesses whether the differences in performance for MQM error types between different MT systems are statistically significant. We conduct a case study for English-to-Croatian, a language direction that involves translating into a morphologically rich language, for which we compare three MT systems belonging to different paradigms: pure phrase-based, factored phrase-based and neural. First, we design an MQM-compliant error taxonomy tailored to the relevant linguistic phenomena of Slavic languages, which made the annotation process feasible and accurate. Errors in MT outputs were then annotated by two annotators following this taxonomy. Subsequently, we carried out a statistical analysis which showed that the best-performing system (neural) reduces the errors produced by the worst system (pure phrase-based) by more than half (54\%). Moreover, we conducted an additional analysis of agreement errors in which we distinguished between short (phrase-level) and long distance (sentence-level) errors. We discovered that phrase-based MT approaches are of limited use for long distance agreement phenomena, for which neural MT was found to be especially effective.Comment: 22 pages, 2 figures, 9 tables, 1 equation. This is a post-peer-review, pre-copyedit version of an article published in Machine Translation Journal. The final authenticated version will be available online at the journal page. arXiv admin note: substantial text overlap with arXiv:1706.0438

Producing Monolingual and ParallelWeb Corpora at the Same Time – SpiderLing and Bitextor’s Love Affair

This paper presents an approach for building large monolingual corpora and, at the same time, extracting parallel data by crawling the top-level domain of a given language of interest. For gathering linguistically relevant data from top-level domains we use the SpiderLing crawler, modified to crawl data written in multiple languages. The output of this process is then fed to Bitextor, a tool for harvesting parallel data from a collection of documents. We call the system combining these two tools Spidextor, a blend of the names of its two crucial parts. We evaluate the described approach intrinsically by measuring the accuracy of the extracted bitexts from the Croatian top-level domain .hr and the Slovene top-level domain .si, and extrinsically on the English–Croatian language pair by comparing an SMT system built from the crawled data with third-party systems. We finally present parallel datasets collected with our approach for the English–Croatian, English–Finnish, English–Serbian and English–Slovene language pairs.This research is supported by the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement PIAP-GA-2012-324414 (AbuMaTran)

Adquisición automática de recursos para traducción automática en el proyecto Abu-MaTran

This paper provides an overview of the research and development activities carried out to alleviate the language resources' bottleneck in machine translation within the Abu-MaTran project. We have developed a range of tools for the acquisition of the main resources required by the two most popular approaches to machine translation, i.e. statistical (corpora) and rule-based models (dictionaries and rules). All these tools have been released under open-source licenses and have been developed with the aim of being useful for industrial exploitation.Este artículo presenta una panorámica de las actividades de investigación y desarrollo destinadas a aliviar el cuello de botella que supone la falta de recursos lingüísticos en el campo de la traducción automática que se han llevado a cabo en el ámbito del proyecto Abu-MaTran. Hemos desarrollado un conjunto de herramientas para la adquisición de los principales recursos requeridos por las dos aproximaciones m as comunes a la traducción automática, modelos estadísticos (corpus) y basados en reglas (diccionarios y reglas). Todas estas herramientas han sido publicadas con licencias libres y han sido desarrolladas con el objetivo de ser útiles para ser explotadas en el ámbito comercial.The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement PIAP-GA-2012-324414 (Abu-MaTran)

Missing information, unresponsive authors, experimental flaws: the impossibility of assessing the reproducibility of previous human evaluations in NLP

We report our efforts in identifying a set of previous humane valuations in NLP that would be suitable for a coordinated study examining what makes human evaluations in NLP more/less reproducible. We present our results and findings, which include that just13% of papers had (i) sufficiently low barriers to reproduction, and (ii) enough obtainable information, to be considered for reproduction, and that all but one of the experiments we selected for reproduction was discovered to have flaws that made the meaningfulness of conducting are production questionable. As a result, we had to change our coordinated study design from a reproduce approach to a standardise-then-reproduce-twice approach. Our overall (negative)finding that the great majority of human evaluations in NLP is not repeatable and/or not reproducible and/or too flawed to justify reproduction, paints a dire picture, but presents an opportunity for a rethink about how to design and report human evaluations in NL

Queer In AI: A Case Study in Community-Led Participatory AI

We present Queer in AI as a case study for community-led participatory design in AI. We examine how participatory design and intersectional tenets started and shaped this community's programs over the years. We discuss different challenges that emerged in the process, look at ways this organization has fallen short of operationalizing participatory and intersectional principles, and then assess the organization's impact. Queer in AI provides important lessons and insights for practitioners and theorists of participatory methods broadly through its rejection of hierarchy in favor of decentralization, success at building aid and programs by and for the queer community, and effort to change actors and institutions outside of the queer community. Finally, we theorize how communities like Queer in AI contribute to the participatory design in AI more broadly by fostering cultures of participation in AI, welcoming and empowering marginalized participants, critiquing poor or exploitative participatory practices, and bringing participation to institutions outside of individual research projects. Queer in AI's work serves as a case study of grassroots activism and participatory methods within AI, demonstrating the potential of community-led participatory methods and intersectional praxis, while also providing challenges, case studies, and nuanced insights to researchers developing and using participatory methods.Comment: To appear at FAccT 202

Fine-grained human evaluation of an English to Croatian hybrid machine translation system

This research compares two approaches to statistical machine translation - pure phrasebased and factored phrase-based - by performing a fine-grained manual evaluation via error annotation of the systems’ outputs, and subsequently analysing the results. The error types considered in the annotation are compliant with the multidimensional quality metrics (MQM), and the annotation is performed by two annotators. Inter-annotator agreement is relatively high for such a task, and the results show that the factored system, i.e. hybrid system, performs much better, reducing the amount of errors produced by the pure phrase-based system by 20%

Inflectional lexicon srLex 1.0

hrLex is an large inflectional lexicon of Serbian language where each entry consists of a (wordform, lemma, MSD) triple. The MSD tagset follows the revised MULTEXT-East V4 tagset for Croatian and Serbian, available at https://github.com/ffnlp/sethr/blob/master/mte4r-upos.mapping