LLMs’ performance on machine translation (MT) tasks is often dependent on the data availability in the specific domains and language pairs that they are trained upon. To examine if multiword expressions (MWEs) still present a bottleneck for LLMs regarding language understanding and translation, we report the performance of systems from the WMT 2026 Test Suites shared task, using portions of the publicly available multilingual parallel corpus AlphaMWE as test suites. We received 31 MT systems’ outputs covering English to Chinese (zh), Polish (pl), German (de), and Arabic (ar) including Modern Standard Arabic (MSA) and two dialectal ones (Egyptian and Tunisian Arabic). We carried out automatic evaluations using BLEU, ChrF, and BERT-score to select the top 3 systems per language pair, followed up with human evaluations on the selected systems. Our findings show that figurative and MWE-related phenomena remain challenging for contemporary MT systems, automatic metrics sometimes disagree in system ranking, and human evaluation uncovers language-specific errors that remain hidden by aggregate scores. Inter-annotator analysis further reveals challenges in consistently identifying and calibrating linguistically subtle translation errors, highlighting the need for explicit evaluation guidelines and careful annotator calibration.

This paper introduces a novel ’universal’ approach to discourse annotation, serving as a comprehensive synthesis of the ISO 24617-8 semantic annotation framework and a newly developed multi-layer model of coherence relations. To address the complexities of text analysis, we present a hierarchical classification and a systematic decision tree. By unifying disparate formalisms, our model provides researchers with a robust, standardised methodology for analysing complex discourse structures across various linguistic contexts.

This study addresses the fundamental task of discourse unit detection – the critical initial step in discourse parsing. We analyze how various discourse frameworks conceptualize and structure discourse units, with a focus on their underlying taxonomies and theoretical assumptions. While approaches to discourse segmentation vary considerably, the extent to which these conceptual divergences influence practical implementations remains insufficiently studied. To address this gap, we investigate similarities and differences in segmentation across several English datasets, segmented and annotated according to distinct discourse frameworks, using a simple, rule-based heuristics. We evaluate the effectiveness of rules with respect to gold-standard segmentation, while also checking variability and cross-framework generalizability. Additionally, we conduct a manual comparison of a sample of rule-based segmentation outputs against benchmark segmentation, identifying points of convergence and divergence.Our findings indicate that discourse frameworks align strongly at the level of segmentation: particular clauses consistently serve as the primary boundaries of discourse units. Discrepancies arise mainly in the treatment of other structures, such as adpositional phrases, appositions, interjections, and parenthesised text segments, which are inconsistently marked as separate discourse units across formalisms.