New Encoders for German Trained from Scratch: Comparing ModernGBERT with Converted LLM2Vec Models

Julia Wunderle, Anton Ehrmanntraut, Jan Pfister, Fotis Jannidis, Andreas Hotho


Abstract
Encoders remain essential for efficient German NLP and NLU scenarios despite the rise of decoder-only LLMs. This work studies two routes to high-quality German encoders under identical data and training constraints: a) training from scratch and b) converting decoders via LLMVec. We introduce two resources: ModernGBERT (134M, 1B), fully transparent German encoders in the ModernBERT style, and LLäMmleinVec (120M, 1B, 7B), decoder-to-encoder conversions trained with masked next-token prediction, both undergoing a context extension to 8192 tokens. Across SuperGLEBer, ModernGBERT 1B sets a new state of the art (avg 0.808), surpassing GBERTlarge (+4%) and the seven-times larger converted 7B model (0.787). On German MTEB after supervised fine-tuning, ModernGBERT 1B (0.551) approaches the converted 7B model (0.557). We release all models, checkpoints, datasets, and full training records, and introduce an encoder-adapted QA-NIAH evaluation. All in all, our results provide actionable guidance: when parameter efficiency and latency matter, from-scratch encoders dominate. When a pre-trained decoder exists and compute is a limited, conversion offers an effective alternative.
Anthology ID:
2026.lrec-main.818
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
10424–10446
Language:
URL:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.818/
DOI:
Bibkey:
Cite (ACL):
Julia Wunderle, Anton Ehrmanntraut, Jan Pfister, Fotis Jannidis, and Andreas Hotho. 2026. New Encoders for German Trained from Scratch: Comparing ModernGBERT with Converted LLM2Vec Models. International Conference on Language Resources and Evaluation, main:10424–10446.
Cite (Informal):
New Encoders for German Trained from Scratch: Comparing ModernGBERT with Converted LLM2Vec Models (Wunderle et al., LREC 2026)
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PDF:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.818.pdf