Rodolfo Zevallos

dblp:271/4848 · also Rodolfo Joel Zevallos Salazar · DBLP profile ↗
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13ranked-venue papers
6as first author
13since 2021 · last 2026
0000-0003-0192-7740ORCID · verified

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 13 · 6 first-author · 13 since 2021Graphics, computer vision, multimedia, augmented reality and games · 5 · 2 first-author · 5 since 2021
YearPublicationVenuePosition
2026 LaFresCat: A studio-quality Catalan multi-accent speech dataset for text-to-speech synthesis
abstract
Current text-to-speech (TTS) systems are capable of learning the phonetics of a language accurately given that the speech data used to train such models covers all phonetic phenomena. For languages with different varieties, this includes all their richness and accents. This is the case of Catalan, a mid-resourced language with several dialects or accents. Although there are various publicly available corpora, there is a lack of high-quality open-access data for speech technologies covering its variety of accents. Common Voice includes recordings of Catalan speakers from different regions; however, accent labeling has been shown to be inaccurate, and artificially enhanced samples may be unsuitable for TTS. To address these limitations, we present LaFresCat, the first studio-quality Catalan multi-accent dataset. LaFresCat comprises 3.5 h of professionally recording speech covering four of the most prominent Catalan accents: Balearic, Central, North-Western, and Valencian. In this work, we provide a detailed description of the dataset design: utterances were selected to be phonetically balanced, detailed speaker instructions were provided, native speakers from the regions corresponding to the Catalan accents were hired, and the recordings were formatted and post-processed. The resulting dataset, LaFresCat, is publicly available. To preliminarily evaluate the dataset, we trained and assessed a lightweight flow-based TTS system, which is also provided as a by-product. We also analyzed LaFresCat samples and the corresponding TTS-generated samples at the phonetic level, employing expert annotations and Pillai scores to quantify acoustic vowel overlap. Preliminary results suggest a significant improvement in predicted mean opinion score (UTMOS), with an increase of 0.42 points when the TTS system is fine-tuned on LaFresCat rather than trained from scratch, starting from a pre-trained version based on Central Catalan data from Common Voice. Subsequent human expert annotations achieved nearly 90% accuracy in accent classification for LaFresCat recordings. However, although the TTS tends to homogenize pronunciation, it still learns distinct dialectal patterns. This assessment offers key insights for establishing a baseline to guide future evaluations of Catalan multi-accent TTS systems and further studies of LaFresCat.
Alex Peiró Lilja, Carme Armentano-Oller, José Giraldo, Wendy Elvira-García, Ignasi Esquerra, Rodolfo Zevallos, Cristina España-Bonet, Martí Llopart-Font, Baybars Külebi, Mireia Farrús
Comput. Speech Lang.6
2025 Lexicography Saves Lives (LSL): Automatically Translating Suicide-Related Language
abstract
Recent years have seen a marked increase in research that aims to identify or predict risk, intention or ideation of suicide. The majority of new tasks, datasets, language models and other resources focus on English and on suicide in the context of Western culture. However, suicide is global issue and reducing suicide rate by 2030 is one of the key goals of the UN’s Sustainable Development Goals. Previous work has used English dictionaries related to suicide to translate into different target languages due to lack of other available resources. Naturally, this leads to a variety of ethical tensions (e.g.: linguistic misrepresentation), where discourse around suicide is not present in a particular culture or country. In this work, we introduce the ‘Lexicography Saves Lives Project’ to address this issue and make three distinct contributions. First, we outline ethical consideration and provide overview guidelines to mitigate harm in developing suicide-related resources. Next, we translate an existing dictionary related to suicidal ideation into 200 different languages and conduct human evaluations on a subset of translated dictionaries. Finally, we introduce a public website to make our resources available and enable community participation.
Annika Marie Schoene, John E. Ortega, Rodolfo Zevallos, Laura Haaber Ihle
COLING3
2025 Evaluating Speech Enhancement Performance Across Demographics and Language
José Giraldo, Alex Peiró Lilja, Carme Armentano-Oller, Rodolfo Zevallos, Cristina España-Bonet
INTERSPEECH4
2025 Towards Domain-Specific Spoken Language Understanding for a Catalan Voice-Controlled Video Game
Alex Peiró Lilja, Rodolfo Zevallos, Carme Armentano-Oller, José Giraldo, Cristina España-Bonet, Mireia Farrús
INTERSPEECH2
2025 Optimizing ASR for Catalan-Spanish Code-Switching: A Comparative Analysis of Methodologies
abstract
Code-switching (CS), the alternating use of two or more languages, challenges automatic speech recognition (ASR) due to scarce training data and linguistic similarities. The lack of dedicated CS datasets limits ASR performance, as most models rely on monolingual or mixed-language corpora that fail to reflect real-world CS patterns. This issue is critical in multilingual societies where CS occurs in informal and formal settings. A key example is Catalan-Spanish CS, widely used in media and parliamentary speeches. In this work, we improve ASR for Catalan-Spanish CS by exploring three strategies: (1) generating synthetic CS data, (2) concatenating monolingual audio, and (3) leveraging real CS data with language tokens. We extract CS data from Catalan speech corpora and fine-tune OpenAI’s Whisper models, making them available on Hugging Face. Results show that combining a modest amount of synthetic CS data with the dominant language token yields the best transcription performance.
Carlos Mena, Pol Serra, Jacobo Romero, Abir Messaoudi, José Giraldo, Carme Armentano-Oller, Rodolfo Zevallos, Iván V. Meza, Javier Hernando
INTERSPEECH7
2025 Assessing the Performance and Efficiency of Mamba ASR in Low-Resource Scenarios
abstract
Mamba, a state space model-based architecture, is emerging as a strong alternative to Transformer models, showing equal or superior performance in sequence generation, including speech. However, analyses have focused mainly on highresource scenarios. This paper explores Mamba’s potential in ASR for low-resource scenarios. We compare the Transformerbased Conformer and its state-space counterpart, ConMamba, across nine languages with varying training data. Our results show that ConMamba achieves similar WER to Conformer for short-context inputs but significantly improves performance on long-context inputs, reducing WER by up to 50% on average. Additionally, ConMamba enhances efficiency, requiring 40–45% less training time, using 50% less memory, and accelerating inference by 63–70%, making it a more effective ASR solution across different data availability scenarios.
Rodolfo Zevallos, Martí Cortada Garcia, Sarah Solito, Carlos Mena, Alex Peiró Lilja, Javier Hernando
INTERSPEECH1
2024 Evaluating Self-Supervised Speech Representations for Indigenous American Languages
abstract
The application of self-supervision to speech representation learning has garnered significant interest in recent years, due to its scalability to large amounts of unlabeled data. However, much progress, both in terms of pre-training and downstream evaluation, has remained concentrated in monolingual models that only consider English. Few models consider other languages, and even fewer consider indigenous ones. In this work, benchmark the efficacy of large SSL models on 6 indigenous America languages: Quechua, Guarani , Bribri, Kotiria, Wa’ikhana, and Totonac on low-resource ASR. Our results show surprisingly strong performance by state-of-the-art SSL models, showing the potential generalizability of large-scale models to real-world data.
Chih-Chen Chen, Rodolfo Zevallos, John E. Ortega
LREC/COLING3
2024 Related Work Is All You Need
abstract
In modern times, generational artificial intelligence is used in several industries and by many people. One use case that can be considered important but somewhat redundant is the act of searching for related work and other references to cite. As an avenue to better ascertain the value of citations and their corresponding locations, we focus on the common “related work” section as a focus of experimentation with the overall objective to generate the section. In this article, we present a corpus with 400k annotations of that distinguish related work from the rest of the references. Additionally, we show that for the papers in our experiments, the related work section represents the paper just as good, and in many cases, better than the rest of the references. We show that this is the case for more than 74% of the articles when using cosine similarity to measure the distance between two common graph neural network algorithms: Prone and Specter.
Rodolfo Zevallos, John E. Ortega, Benjamin Irving
LREC/COLING1
2024 TEMA: Token Embeddings Mapping for Enriching Low-Resource Language Models
abstract
The objective of the research we present is to remedy the problem of the low quality of language models for low-resource languages.We introduce an algorithm, the Token Embedding Mapping Algorithm (TEMA), that maps the token embeddings of a richly pre-trained model L1 to a poorly trained model L2, thus creating a richer L2' model.Our experiments show that the L2' model reduces perplexity with respect to the original monolingual model L2, and that for downstream tasks, including SuperGLUE, the results are state-of-the-art or better for the most semantic tasks.The models obtained with TEMA are also competitive or better than multilingual or extended models proposed as solutions for mitigating the low-resource language problems.
Rodolfo Zevallos, Núria Bel, Mireia Farrús
EMNLP1
2023 Hints on the data for language modeling of synthetic languages with transformers
abstract
Language Models (LM) are becoming more and more useful for providing representations upon which to train Natural Language Processing applications.However, there is now clear evidence that attention-based transformers require a critical amount of language data to produce good enough LMs.The question we have addressed in this paper is to what extent the critical amount of data varies for languages of different morphological typology, in particular those that have a rich inflectional morphology, and whether the tokenization method to preprocess the data can make a difference.These details can be important for low-resource languages that need to plan the production of datasets.We evaluated intrinsically and extrinsically the differences of five different languages with different pretraining dataset sizes and three different tokenization methods for each.The results confirm that the size of the vocabulary due to morphological characteristics is directly correlated with both the LM perplexity and the performance of two typical downstream tasks such as NER identification and POS Tagging.The experiments also provide new evidence that a canonical tokenizer can reduce perplexity by more than a half for a polysynthetic language like Quechua as well as raising macro-F1 score from 0.8 to more than 0.9 in both downstream tasks with a LM trained with only 6M tokens. 1 .
Rodolfo Zevallos, Núria Bel
ACL (1)1
2022 WordNet-QU: Development of a Lexical Database for Quechua Varieties
abstract
In the effort to minimize the risk of extinction of a language, linguistic resources are fundamental. Quechua, a low-resource language from South America, is a language spoken by millions but, despite several efforts in the past, still lacks the resources necessary to build high-performance computational systems. In this article, we present WordNet-QU which signifies the inclusion of Quechua in a well-known lexical database called wordnet. We propose WordNet-QU to be included as an extension to wordnet after demonstrating a manually-curated collection of multiple digital resources for lexical use in Quechua. Our work uses the synset alignment algorithm to compare Quechua to its geographically nearest high-resource language, Spanish. Altogether, we propose a total of 28,582 unique synset IDs divided according to region like so: 20510 for Southern Quechua, 5993 for Central Quechua, 1121 for Northern Quechua, and 958 for Amazonian Quechua.
Nelsi Melgarejo, Rodolfo Zevallos, Hector Gomez, John E. Ortega
COLING2
2022 Data Augmentation for Low-Resource Quechua ASR Improvement
abstract
Comunicació presentada a INTERSPEECH 2022, celebrat del 18 al 22 de setembre de 2022 a Inchon, Corea del Sud.
Rodolfo Zevallos, Núria Bel, Guillermo Cámbara, Mireia Farrús, Jordi Luque
INTERSPEECH1
2022 Huqariq: A Multilingual Speech Corpus of Native Languages of Peru forSpeech Recognition
abstract
The Huqariq corpus is a multilingual collection of speech from native Peruvian languages. The transcribed corpus is intended for the research and development of speech technologies to preserve endangered languages in Peru. Huqariq is primarily designed for the development of automatic speech recognition, language identification and text-to-speech tools. In order to achieve corpus collection sustainably, we employs the crowdsourcing methodology. Huqariq includes four native languages of Peru, and it is expected that by the year 2022, it can reach up to 20 native languages out of the 48 native languages in Peru. The corpus has 220 hours of transcribed audio recorded by more than 500 volunteers, making it the largest speech corpus for native languages in Peru. In order to verify the quality of the corpus, we present speech recognition experiments using 220 hours of fully transcribed audio.
Rodolfo Zevallos, Luis Camacho, Nelsi Melgarejo
LREC1