Mutarjim: Advancing Bidirectional Arabic-English Translation with a
  Small Language Model
Authors: name: Khalil Hennara; name: Muhammad Hreden; name: Mohamed Motaism Hamed; name: Zeina Aldallal; name: Sara Chrouf; name: Safwan AlModhayan
Published: 2025-05-23 13:42:21

Abstract: We introduce Mutarjim, a compact yet powerful language model for
bidirectional Arabic-English translation. While large-scale LLMs have shown
impressive progress in natural language processing tasks, including machine
translation, smaller models. Leveraging this insight, we developed Mutarjim
based on Kuwain-1.5B , a language model tailored for both Arabic and English.
Despite its modest size, Mutarjim outperforms much larger models on several
established benchmarks, achieved through an optimized two-phase training
approach and a carefully curated, high-quality training corpus.. Experimental
results show that Mutarjim rivals models up to 20 times larger while
significantly reducing computational costs and training requirements. We also
introduce Tarjama-25, a new benchmark designed to overcome limitations in
existing Arabic-English benchmarking datasets, such as domain narrowness, short
sentence lengths, and English-source bias. Tarjama-25 comprises 5,000
expert-reviewed sentence pairs and spans a wide range of domains, offering a
more comprehensive and balanced evaluation framework. Notably, Mutarjim
achieves state-of-the-art performance on the English-to-Arabic task in
Tarjama-25, surpassing even significantly larger and proprietary models like
GPT-4o mini. We publicly release Tarjama-25 to support future research and
advance the evaluation of Arabic-English translation systems.