Janaki Sheth, Young-Suk Lee, Ramón Fernandez Astudillo, Tahira Naseem, Radu Florian, Salim Roukos, Todd Ward. Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume. 2021.

Vittorio Castelli, Rishav Chakravarti, Saswati Dana, Anthony Ferritto, Radu Florian, Martin Franz, Dinesh Garg, Dinesh Khandelwal, Scott McCarley, Michael McCawley, Mohamed Nasr, Lin Pan, Cezar Pendus, John Pitrelli, Saurabh Pujar, Salim Roukos, Andrzej Sakrajda, Avi Sil, Rosario Uceda-Sosa, Todd Ward, Rong Zhang. Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics. 2020.

Rong Zhang, Revanth Gangi Reddy, Md Arafat Sultan, Vittorio Castelli, Anthony Ferritto, Radu Florian, Efsun Sarioglu Kayi, Salim Roukos, Avi Sil, Todd Ward. Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP). 2020.

Multilingual machine translation addresses the task of translating between multiple source and target languages. We propose task-specific attention models, a simple but effective technique for improving the quality of sequence-to-sequence neural multilingual translation. Our approach seeks to retain as much of the parameter sharing generalization of NMT models as possible, while still allowing for language-specific specialization of the attention model to a particular language-pair or task. Our experiments on four languages of the Europarl corpus show that using a target-specific model of attention provides consistent gains in translation quality for all possible translation directions, compared to a model in which all parameters are shared. We observe improved translation quality even in the (extreme) low-resource zero-shot translation directions for which the model never saw explicitly paired parallel data.

Much is known about the design of automated systems to search broadcast news, but it has only recently become possible to apply similar techniques to large collections of spontaneous speech. This paper presents initial results from experiments with speech recognition, topic segmentation, topic categorization, and named entity detection using a large collection of recorded oral histories. The work leverages a massive manual annotation effort on 10 000 h of spontaneous speech to evaluate the degree to which automatic speech recognition (ASR)-based segmentation and categorization techniques can be adapted to approximate decisions made by human annotators. ASR word error rates near 40% were achieved for both English and Czech for heavily accented, emotional and elderly spontaneous speech based on 65-84 h of transcribed speech. Topical segmentation based on shifts in the recognized English vocabulary resulted in 80% agreement with manually annotated boundary positions at a 0.35 false alarm rate. Categorization was considerably more challenging, with a nearest-neighbor technique yielding F=0.3. This is less than half the value obtained by the same technique on a standard newswire categorization benchmark, but replication on human-transcribed interviews showed that ASR errors explain little of that difference. The paper concludes with a description of how these capabilities could be used together to search large collections of recorded oral histories.

Digital archives have emerged as the pre-eminent method for capturing the human experience. Before such archives can be used efficiently, their contents must be described. The scale of such archives along with the associated content mark up cost make it impractical to provide access via purely manual means, but automatic technologies for search in spoken materials still have relatively limited capabilities. The NSF-funded MALACH project will use the world’s largest digital archive of video oral histories, collected by the Survivors of the Shoah Visual History Foundation (VHF) to make a quantum leap in the ability to access such archives by advancing the state-of-the-art in Automated Speech Recognition (ASR), Natural Language Processing (NLP) and related technologies [1, 2]. This corpus consists of over 115,000 hours of unconstrained, natural speech from 52,000 speakers in 32 different languages, filled with disfluencies, heavy accents, age-related coarticulations, and un-cued speaker and language switching. This paper discusses some of the ASR and NLP tools and technologies that we have been building for the English speech in the MALACH corpus. We also discuss this new test bed while emphasizing the unique characteristics of this corpus. 1.

Human evaluations of machine translation are extensive but expensive. Human evaluations can take months to finish and involve human labor that can not be reused. We propose a method of automatic machine translation evaluation that is quick, inexpensive, and language-independent, that correlates highly with human evaluation, and that has little marginal cost per run. We present this method as an automated understudy to skilled human judges which substitutes for them when there is need for quick or frequent evaluations.

The TREC Spoken Document Retrieval Track (SDR) and the Topic Detection and Tracking (TDT) project have annotated the same corpus with difference styles of relevance judgements, using differenct notions of topic. We compare the behavior of a topic tracking system using relevance judgements from TDT with that of the same system using relevance from the SDR in order to investigate the influence of differences document relevance judgements on the behavior of the tracking system.

We investigate important differences between two styles of document clustering in the context of Topic Detection and Tracking. Converting a Topic Detection system into a Topic Tracking system exposes fundamental differences between these two tasks that are important to consider in both the design and the evaluation of TDT systems. We also identify features that can be used in systems for both tasks.

Our English-Chinese cross-language IR system is trained from parallel corpora; we investigate its performance as a function of training corpus size for three different training corpora. We find that the performance of the system as trained on the three parallel corpora can be related by a simple measure, namely the out-of-vocabulary rate of query words.

We describe our development work on a telephonebased conversational system in the domain of mutual fund transactions. This system uses several components including robust large vocabulary continuous speech recognition, natural language understanding, dialog management, and text-to-speech synthesis technologies.

We present a technique for the segmention of a sound track into two classes of segments. Each frame of signal is preprocessed by extracting cepstral coefficients and their first order derivatives. For each class, the distribution of the frame parameter vectors is modeled by a Gaussian Mixture Model (GMM). GMM order is selected using two criteria : the Minimum Description Length (MDL) criterion and the Akaike Information Criterion (AIC). Frame score is based on a weighted loglikelihood ratio in a window around the frame. Decision for each frame is taken by comparing its score to a threshold. Experiments are presented on speech / music segmentation in audio tracks. In these experiments, the MDL criterion leads to a reasonable GMM order. Using the MDL criterion for GMM order selection, frame classification error rate is around 20%. However, using GMMs with much lower orders, only decreases marginally performances.

In natural language, some sequences of words are very frequent.A classical language model, like n-gram, does not adequately take into account such sequences, because it underestimates their probabilities.A better approach consists in modeling word sequences as if they were individual dictionary elements.Sequences are considered as additional entries of the word lexicon, on which language models are computed.In this paper, we present two methods for automatically determining frequent phrases in unlabeled corpora of written sentences.These methods are based on information theoretic criteria which insure a high statistical consistency.Our models reach their local optimum since they minimize the perplexity.One procedure is based only on the n-gram language model to extract word sequences.The second one is based on a class n-gram model trained on 233 classes extracted from the eight grammatical classes of French.Experimental tests, in terms of perplexity and recognition rate, are carried out on a vocabulary of 20000 words and a corpus of 43 million words extracted from the "Le Monde" newspaper.Our models reduce perplexity by more than 20% compared with n-gram (nR3) and multigram models.In terms of recognition rate, our models outperform n-gram and multigram models.

We consider translating natural language sentences into a formal language using direct translation models built automatically from training data. Direct translation models have three components: an arbitrary prior conditional probability distribution, features that capture correlations between automatically determined key phrases or sets of words in both languages, and weights associated with these features. The features and the weights are selected using a training corpus of matched pairs of source and target language sentences to maximize the entropy or a new discrimination measure of the resulting conditional probability model. We report results in the air travel information system domain and compare the two methods of training.

In this paper we describe our initial eorts in build-ing a natural language understanding (NLU) system across multiple languages. The system allows users to switch lan-guages seamlessly in a single session without requiring any switch in the speech recognition system. Context depen-dence is maintained across sentences, even when the user changes languages. Towards this end we have begun build-ing a universal speech recognizer for English and French languages. We experiment with a universal phonology for both French and English with a novel mechanism to han-dle language dependent variations. Our best results so far show about 5 % relative performance degradation for Eng-lish relative to a unilingual English system and a 9 % rela-tive degradation in French relative to a unilingual French system. The NLU system uses the same statistical un-derstanding algorithms for each language, making system development, maintenance, and portability vastly superior to systems built customly for each language. 1.

Several recent efforts in statistical natural language understanding (NLU) have focused on generating clumps of English words from semantic meaning concepts (Miller et al., 1995; Levin and Pieracini, 1995; Epstein et al., 1996; Epstein, 1996). This paper extends the IBM Machine Translation Group's concept of fertility (Brown et al., 1993) to the generation of clumps for natural language understanding. The basic underlying intuition is that a single concept may be expressed in English as many disjoint clump of words. We present two fertility models which attempt to capture this phenomenon. The first is a Poisson model which leads to appealing computational simplicity. The second is a general nonparametric fertility model. The general model's parameters are boot-strapped from the Poisson model and updated by the EM algorithm. These fertility models can be used to impose clump fertility structure on top of preexisting clump generation models. Here, we present results for adding fertility structure to unigram, bigram, and headword clump generation models on ARPA's Air Travel Information Service (ATIS) domain.

We present a new approach to natural language understanding (NLU) based on the source-channel paradigm, and apply it to ARPA's Air Travel Information Service (ATIS) domain. The model uses techniques similar to those used by IBM in statistical machine translation. The parameters are trained using the exact match algorithm; a hierarchy of models is used to facilitate the bootstrapping of more complex models from simpler models.

this paper, we present a method where more of the tree structure is used in the parsing model. We define a set of features that capture long distance dependency such as parallelism in coordination. These features are then integrated with a Maximum Entropy model into an overall probabilistic model for parsing. We introduce the decision tree parser in Section 2, describe the Maximum Entropy model in Section 3, describe the feature extraction algorithm in Section 4, give experimental results in Section 5, and present our conclusions in Section 6.