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Main Authors: Uğur, Özgür, Göksu, Mahmut, Çimen, Mahmut, Yılmaz, Musa, Şavirdi, Esra, Demir, Alp Talha, Güllüce, Rumeysa, Çetin, İclal, Sağbaş, Ömer Can
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.16018
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author Uğur, Özgür
Göksu, Mahmut
Çimen, Mahmut
Yılmaz, Musa
Şavirdi, Esra
Demir, Alp Talha
Güllüce, Rumeysa
Çetin, İclal
Sağbaş, Ömer Can
author_facet Uğur, Özgür
Göksu, Mahmut
Çimen, Mahmut
Yılmaz, Musa
Şavirdi, Esra
Demir, Alp Talha
Güllüce, Rumeysa
Çetin, İclal
Sağbaş, Ömer Can
contents This paper presents Mecellem models, a framework for developing specialized language models for the Turkish legal domain through domain adaptation strategies. We make two contributions: (1)Encoder Model Pre-trained from Scratch: ModernBERT-based bidirectional encoders pre-trained on a Turkish-dominant corpus of 112.7 billion tokens. We implement a checkpoint selection strategy that evaluates downstream retrieval performance throughout training, revealing that optimal checkpoints achieve best retrieval scores before pre-training loss reaches its minimum. Our encoder models achieve top-3 rankings on the Turkish retrieval leaderboard, with smaller models (155M parameters) achieving comparable performance to larger reference models (307M-567M parameters). Our approach achieves 92.36% production efficiency compared to state-of-the-art models (embeddinggemma-300m: 100.00%, BAAI/bge-m3: 99.54%, newmindai/bge-m3-stsb: 94.38%), ranking fourth overall despite requiring less computational resources. SOTA models rely on multi-stage, computationally intensive training pipelines, making our single-stage pre-training followed by efficient post-training approach a cost-effective alternative; (2)Decoder Model with Continual Pre-training (CPT): Qwen3-1.7B and Qwen3-4B models adapted to Turkish legal domain through controlled curriculum learning. Four-phase CPT with optimal sample ratios enables gradual transition from general language knowledge to specialized legal terminology and long-context reasoning. This approach achieves 36.2% perplexity reduction on Turkish legal text, demonstrating domain adaptation gains.
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id arxiv_https___arxiv_org_abs_2601_16018
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mecellem Models: Turkish Models Trained from Scratch and Continually Pre-trained for the Legal Domain
Uğur, Özgür
Göksu, Mahmut
Çimen, Mahmut
Yılmaz, Musa
Şavirdi, Esra
Demir, Alp Talha
Güllüce, Rumeysa
Çetin, İclal
Sağbaş, Ömer Can
Computation and Language
This paper presents Mecellem models, a framework for developing specialized language models for the Turkish legal domain through domain adaptation strategies. We make two contributions: (1)Encoder Model Pre-trained from Scratch: ModernBERT-based bidirectional encoders pre-trained on a Turkish-dominant corpus of 112.7 billion tokens. We implement a checkpoint selection strategy that evaluates downstream retrieval performance throughout training, revealing that optimal checkpoints achieve best retrieval scores before pre-training loss reaches its minimum. Our encoder models achieve top-3 rankings on the Turkish retrieval leaderboard, with smaller models (155M parameters) achieving comparable performance to larger reference models (307M-567M parameters). Our approach achieves 92.36% production efficiency compared to state-of-the-art models (embeddinggemma-300m: 100.00%, BAAI/bge-m3: 99.54%, newmindai/bge-m3-stsb: 94.38%), ranking fourth overall despite requiring less computational resources. SOTA models rely on multi-stage, computationally intensive training pipelines, making our single-stage pre-training followed by efficient post-training approach a cost-effective alternative; (2)Decoder Model with Continual Pre-training (CPT): Qwen3-1.7B and Qwen3-4B models adapted to Turkish legal domain through controlled curriculum learning. Four-phase CPT with optimal sample ratios enables gradual transition from general language knowledge to specialized legal terminology and long-context reasoning. This approach achieves 36.2% perplexity reduction on Turkish legal text, demonstrating domain adaptation gains.
title Mecellem Models: Turkish Models Trained from Scratch and Continually Pre-trained for the Legal Domain
topic Computation and Language
url https://arxiv.org/abs/2601.16018