Assisting Corpus Annotation: Automatic BIO-Tagging of Clause-Like Units in Polish Sign Language. A Pilot Study on Corpus Data

Piotr Mostowski, Anna Kuder, Joanna Wójcicka


Abstract
The creation of large-scale sign language corpora is often bottlenecked by the labour-intensive process of multi-layered annotation that requires manual analysis. One of the annotation steps is the challenging and time-consuming task of segmenting continuous signing into clause-like-units (CLUs). In this paper, we propose an automated segmentation framework for Polish Sign Language (PJM) designed to support manual annotation. To detect sentence boundaries, we adapt the Multi-Stage Temporal Convolutional Network (MS-TCN) architecture, enhanced with a Channel Attention mechanism, to effectively fuse multimodal skeleton features (hands, body, and face) extracted via MediaPipe. We evaluate the model on a diverse subset of the PJM Corpus (40 video files, 25 signers), containing nearly 16,000 manually annotated clauses prior to the start of this study. The proposed method achieves a Segmental F1-score of 75.43% at IoU = 0.10 and 57.52% at IoU = 0.50, demonstrating a strong capability in localising sentence boundaries. Furthermore, ablation studies reveal that fusing manual kinematics with non-manual prosodic cues (face) yields a significant performance gain (+13.6 pp) over unimodal baselines, empirically confirming the linguistic necessity of incorporating both manual and non-manual articulators in the process of sentence delimitation. The solution offers a viable means for reducing CLU annotation time by automatically generating high-quality clause boundary proposals.
Anthology ID:
2026.signlang-1.37
Volume:
Proceedings of the LREC 2026 12th Workshop on the Representation and Processing of Sign Languages: Language in Motion
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Eleni Efthimiou, Stavroula-Evita Fotinea, Thomas Hanke, Julie A. Hochgesang, Johanna Mesch, Marc Schulder
Venues:
SignLang | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
351–360
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-signlang-37
DOI:
10.63317/364zmis7ppgo
Bibkey:
Cite (ACL):
Piotr Mostowski, Anna Kuder, and Joanna Wójcicka. 2026. Assisting Corpus Annotation: Automatic BIO-Tagging of Clause-Like Units in Polish Sign Language. A Pilot Study on Corpus Data. In Proceedings of the LREC 2026 12th Workshop on the Representation and Processing of Sign Languages: Language in Motion, pages 351–360, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
Assisting Corpus Annotation: Automatic BIO-Tagging of Clause-Like Units in Polish Sign Language. A Pilot Study on Corpus Data (Mostowski et al., SignLang 2026)
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