Christian Gollan


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End-to-End Speech Translation for Code Switched Speech
Orion Weller | Matthias Sperber | Telmo Pires | Hendra Setiawan | Christian Gollan | Dominic Telaar | Matthias Paulik
Findings of the Association for Computational Linguistics: ACL 2022

Code switching (CS) refers to the phenomenon of interchangeably using words and phrases from different languages. CS can pose significant accuracy challenges to NLP, due to the often monolingual nature of the underlying systems. In this work, we focus on CS in the context of English/Spanish conversations for the task of speech translation (ST), generating and evaluating both transcript and translation. To evaluate model performance on this task, we create a novel ST corpus derived from existing public data sets. We explore various ST architectures across two dimensions: cascaded (transcribe then translate) vs end-to-end (jointly transcribe and translate) and unidirectional (source -> target) vs bidirectional (source <-> target). We show that our ST architectures, and especially our bidirectional end-to-end architecture, perform well on CS speech, even when no CS training data is used.


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Streaming Models for Joint Speech Recognition and Translation
Orion Weller | Matthias Sperber | Christian Gollan | Joris Kluivers
Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume

Using end-to-end models for speech translation (ST) has increasingly been the focus of the ST community. These models condense the previously cascaded systems by directly converting sound waves into translated text. However, cascaded models have the advantage of including automatic speech recognition output, useful for a variety of practical ST systems that often display transcripts to the user alongside the translations. To bridge this gap, recent work has shown initial progress into the feasibility for end-to-end models to produce both of these outputs. However, all previous work has only looked at this problem from the consecutive perspective, leaving uncertainty on whether these approaches are effective in the more challenging streaming setting. We develop an end-to-end streaming ST model based on a re-translation approach and compare against standard cascading approaches. We also introduce a novel inference method for the joint case, interleaving both transcript and translation in generation and removing the need to use separate decoders. Our evaluation across a range of metrics capturing accuracy, latency, and consistency shows that our end-to-end models are statistically similar to cascading models, while having half the number of parameters. We also find that both systems provide strong translation quality at low latency, keeping 99% of consecutive quality at a lag of just under a second.


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Consistent Transcription and Translation of Speech
Matthias Sperber | Hendra Setiawan | Christian Gollan | Udhyakumar Nallasamy | Matthias Paulik
Transactions of the Association for Computational Linguistics, Volume 8

The conventional paradigm in speech translation starts with a speech recognition step to generate transcripts, followed by a translation step with the automatic transcripts as input. To address various shortcomings of this paradigm, recent work explores end-to-end trainable direct models that translate without transcribing. However, transcripts can be an indispensable output in practical applications, which often display transcripts alongside the translations to users.We make this common requirement explicit and explore the task of jointly transcribing and translating speech. Although high accuracy of transcript and translation are crucial, even highly accurate systems can suffer from inconsistencies between both outputs that degrade the user experience. We introduce a methodology to evaluate consistency and compare several modeling approaches, including the traditional cascaded approach and end-to-end models. We find that direct models are poorly suited to the joint transcription/translation task, but that end-to-end models that feature a coupled inference procedure are able to achieve strong consistency. We further introduce simple techniques for directly optimizing for consistency, and analyze the resulting trade-offs between consistency, transcription accuracy, and translation accuracy.1


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TC-STAR: New language resources for ASR and SLT purposes
Henk van den Heuvel | Khalid Choukri | Christian Gollan | Asuncion Moreno | Djamel Mostefa
Proceedings of the Fifth International Conference on Language Resources and Evaluation (LREC’06)

In TC-STAR a variety of Language Resources (LR) is being produced. In this contribution we address the resources that have been created for Automatic Speech Recrognition and Spoken Language Translation. As yet, these are 14 LR in total: two training SLR for ASR (English and Spanish), three development LR and three evaluation LR for ASR (English, Spanish, Mandarin), and three development LR and three evaluation LR for SLT (English-Spanish, Spanish-English, Mandarin-English). In this paper we describe the properties, validation, and availability of these resources.