activity
20202026
most citedX-Stance: A Multilingual Multi-Target Dataset for Stance Detection

46 citations · 50 across the 14 of their papers we have counts for

collaborators

15 papers

cs.CL2026

RUMLEM: A Dictionary-Based Lemmatizer for Romansh

Dominic P. Fischer, Zachary Hopton, Jannis Vamvas

Lemmatization -- the task of mapping an inflected word form to its dictionary form -- is a crucial component of many NLP applications. In this paper, we present RUMLEM, a lemmatize…

cs.CL2026

Robust Language Identification for Romansh Varieties

Charlotte Model, Sina Ahmadi, Jannis Vamvas

The Romansh language has several regional varieties, called idioms, which sometimes have limited mutual intelligibility. Despite this linguistic diversity, there has been a lack of…

cs.CL2025

SwissGov-RSD: A Human-annotated, Cross-lingual Benchmark for Token-level Recognition of Semantic Differences Between Related Documents

Michelle Wastl, Jannis Vamvas, Rico Sennrich

Recognizing semantic differences across documents is crucial for text generation evaluation and content alignment, especially in cross-lingual settings. However, as a standalone ta…

cs.CL2025

QueST: Incentivizing LLMs to Generate Difficult Problems

Hanxu Hu, Xingxing Zhang, Jannis Vamvas +2

Large Language Models have achieved strong performance on reasoning tasks, solving competition-level coding and math problems. However, their scalability is limited by human-labele…

cs.CL2025

The Mediomatix Corpus: Parallel Data for Romansh Language Varieties via Comparable Schoolbooks

Zachary Hopton, Jannis Vamvas, Andrin Büchler +3

The five idioms (i.e., varieties) of the Romansh language are largely standardized and are taught in the schools of the respective communities in Switzerland. In this paper, we pre…

cs.CL2025

20min-XD: A Comparable Corpus of Swiss News Articles

Michelle Wastl, Jannis Vamvas, Selena Calleri +1

We present 20min-XD (20 Minuten cross-lingual document-level), a French-German, document-level comparable corpus of news articles, sourced from the Swiss online news outlet 20 Minu…

cs.CL2025

Source-primed Multi-turn Conversation Helps Large Language Models Translate Documents

Hanxu Hu, Jannis Vamvas, Rico Sennrich

LLMs have paved the way for truly simple document-level machine translation, but challenges such as omission errors remain. In this paper, we study a simple method for handling doc…

cs.CL2023

Investigating Multi-Pivot Ensembling with Massively Multilingual Machine Translation Models

Alireza Mohammadshahi, Jannis Vamvas, Rico Sennrich

Massively multilingual machine translation models allow for the translation of a large number of languages with a single model, but have limited performance on low- and very-low-re…

cs.CL2023★ 2 cited

Mitigating Hallucinations and Off-target Machine Translation with Source-Contrastive and Language-Contrastive Decoding

Rico Sennrich, Jannis Vamvas, Alireza Mohammadshahi

Hallucinations and off-target translation remain unsolved problems in MT, especially for low-resource languages and massively multilingual models. In this paper, we introduce two r…

cs.CL2023

Towards Unsupervised Recognition of Token-level Semantic Differences in Related Documents

Jannis Vamvas, Rico Sennrich

Automatically highlighting words that cause semantic differences between two documents could be useful for a wide range of applications. We formulate recognizing semantic differenc…

cs.CL2023★ 1 cited

SwissBERT: The Multilingual Language Model for Switzerland

Jannis Vamvas, Johannes Graën, Rico Sennrich

We present SwissBERT, a masked language model created specifically for processing Switzerland-related text. SwissBERT is a pre-trained model that we adapted to news articles writte…

cs.CL2022★ 1 cited

NMTScore: A Multilingual Analysis of Translation-based Text Similarity Measures

Jannis Vamvas, Rico Sennrich

Being able to rank the similarity of short text segments is an interesting bonus feature of neural machine translation. Translation-based similarity measures include direct and piv…

cs.CL2022

As Little as Possible, as Much as Necessary: Detecting Over- and Undertranslations with Contrastive Conditioning

Jannis Vamvas, Rico Sennrich

Omission and addition of content is a typical issue in neural machine translation. We propose a method for detecting such phenomena with off-the-shelf translation models. Using con…

cs.CL2021

On the Limits of Minimal Pairs in Contrastive Evaluation

Jannis Vamvas, Rico Sennrich

Minimal sentence pairs are frequently used to analyze the behavior of language models. It is often assumed that model behavior on contrastive pairs is predictive of model behavior…

cs.CL2020★ 46 cited

X-Stance: A Multilingual Multi-Target Dataset for Stance Detection

Jannis Vamvas, Rico Sennrich

We extract a large-scale stance detection dataset from comments written by candidates of elections in Switzerland. The dataset consists of German, French and Italian text, allowing…